Joel Hills says no buyer wants to touch Tata Steel's UK pension liabilities "with a barge pole".
The government is considering changes to pension laws to reduce the burden and attract investment.
Our business editor says this could have wide-reaching implications beyond the steel sector.
The government is "going down a very dangerous path" in seeking to change pension laws to save Tata Steel's UK operation, an ex-Liberal Democrat pensions minister has said.
Steve Webb said any changes could affect the pension security of "hundreds of thousands of workers, well beyond the steel industry".
Everyone has huge sympathy for steel workers and for efforts to protect jobs, but rushed changes to pension rules risk driving a coach and horses through the pension security of hundreds of thousands of workers, well beyond the steel industry.
The rules to protect pensions have been carefully worked out over many years.
Rushed legislation could open the floodgates to employers who may wish to walk away from their pension schemes rather than honour their pension promises.
The Government must tread very carefully in this area.
Steelworkers' pensions must be protected in any plan to save Tata Steel's UK operation, Labour has said.
ITV News understands ministers are exploring ways of reducing the firm's UK pension burden in a bid to attract buyers.
Reacting to the reports, Owen Smith, Labour's shadow work and pensions secretary, said:
Dealing with the Tata pension scheme must be a central part of any Government package to save our steel industry, so it will be totally inappropriate for Ministers to rush out this vital announcement, in a written statement without any scrutiny on the final day before a recess.
Steel workers’ pensions must be protected, they’ve earned them with hard graft over many years.
So if Ministers are considering measures which might see those pensions reduced, MPs from all parties, especially those representing steel communities, will want a chance to question the plans, along with the trade unions who are playing such a vital and impressive role standing up for Tata workers.
If these reports are accurate, the Secretary of State for Work and Pensions should come to the House to explain precisely what is being proposed, including how current and future steel pensioners will be affected and what precedents might be set by any changes to hard won pension protection legislation.
Ministers are considering changes to pension laws in an attempt to persuade Tata abandon its planned sell-off.Read the full story ›
Ministers are considering far-reaching changes to pension laws in an attempt to prevent the loss of Indian conglomerate Tata's UK steel-making assets, it has been reported.
It comes as today hundreds of steel workers marched through London to demand the Government ensures the responsible sale of Tata Steel's UK assets - which include Hartlepool Pipe Mill.
Channel 4 News reported the Government was looking at ways of helping Tata to ease its pension liabilities in an effort to persuade it to abandon its planned sell-off.
The Department for Business, Innovation and Skills refused to comment ahead of a planned Commons statement by Business Secretary Sajid Javid on Thursday.
However Business Minister Anna Soubry said the Government had always made clear it would do "everything we can" to look at the pensions issue.
Ms Soubry told Channel 4 News:
We have always said we would do everything we can to look at pensions. We are determined to keep our steel industry.
The Prime Minister said 'no stone to be unturned' and that is exactly what has been done."
Welsh First Minister Carwyn Jones, who has been with Mr Javid in Mumbai for talks with Tata, said that he was urging the Government to make legal changes.
Mr Jones said he believed there were ways of dealing with the pensions issue without putting the fund into the Government's Pensions Protection Fund lifeboat- which would mean members losing benefits.
"The UK Government has more levers it can pull than we can with its control of the tax system and pensions legislation," he told the programme.
"There are ways of looking to change the law on this and we would urge the UK Government to do that."
"It's right to say - let's not pretend otherwise - that it's unlikely that any buyer will come forward with the pension liability there."
Middlesbrough South and East Cleveland MP Tom Blenkinsop has questioned the Chancellor on government steel policy in Parliament.
Hundreds of steelworkers from across the country are marching through London today to demand the Government ensures the responsible sale of Tata Steel's UK assets - which include Hartlepool Pipe Mill.
Blenkinsop said the Chancellor was putting his own interests ahead of British steelworkers.
Why does this Government back China's bid for market economy status against the interests of British steelworkers. Why does this Chancellor block changes against the lesser duty tariffs against the interest of British steelworkers?
And when will he set down an industrial strategy to put British steelworkers interests ahead of his own?"
The Chancellor said the Government had imposed tariffs on Chinese dumping.
"We have taken action to reduce energy charges on energy intensive industries."
"We have taken action to make sure there's more flexibility with emission regulations, doing everything we can to help this industry in a very difficult time including making sure there are tough tariffs on Chinese dumping and as a results of the tariffs that have been introduced on steel those imports are down 19%."
Hundreds of steelworkers from across the country are marching through London to demand the Government ensures the responsible sale of Tata Steel's UK assets - which include Hartlepool Pipe Mill.
It comes ahead of a meeting between Tata Steel board members in Mumbai to draw up a shortlist of potential buyers.
Two companies have now made formal bids to take over Tata Steel's UK operations.
Liberty House, the commodities group, and Excalibur Steel UK say they have both registered letters of intent with the firm. If a deal is agreed, 500 jobs at Tata's Hartlepool Beam Mill could be safeguarded.
Liberty House says its business model would move towards recycling steel rather than producing it in blast furnaces.
Liberty House Group has confirmed it has formally submitted the required letter of intent to Tata Steel Europe containing its indicative bid for all of Tata Steel's UK assets.
A statement said:
The document, which was sent from Liberty's international headquarters in London, states the company's intention to bid for all of Tata Steel's UK assets, excluding its Long Products division which is in the process of being sold separately, and the Scottish Plate Assets that Liberty already acquired from Tata.
The bid is based on Liberty's greensteel business model and would involve a transition from steelmaking in blast furnaces to recycling steel in electric arc furnaces over time, while ensuring the company continues to meet key customers' quality requirements. Steelmaking would be ultimately powered by renewable energy sources.
Liberty believes the UK steel industry can achieve long-term viability if based on an agile, sustainable, non-cyclical model which integrates liquid steel-making from recycling with down-stream production and the manufacture of advanced engineering products.