Two peers have been suspended from the Labour Party over claims they offered to carry out parliamentary work in return for cash. Lord Laird earlier resigned the Ulster Unionist party whip after being targeted by the same investigation.
Labour peer Lord Mackenzie insisted he had "done nothing wrong" and claimed he had not breached parliamentary rules following lobbying claims.
"I've obeyed the rules. I know what the rules are - obviously I studied them before I get involved in these sort of issues," he said, speaking before the Labour Party announced that he had been suspended pending further investigation.
He said he had been considering "perhaps taking a consultancy" with a solar energy glazing firm, which "sounded like quite an interesting and novel thing" because of his interest in energy policy.
Lord Mackenzie of Framwellgate tells me he has done nothing wrong in the "cash for access" row, insisting he stuck by parliamentary rules, and if this is deemed wrong, it is the rules that need changing.
International Development Secretary Justine Greening told ITV News that the main political parties "need to look more carefully at lobbying" in the light of allegations made in the Sunday Times, the Telegraph and on BBC's Panorama programme.
She stopped short of saying that a statutory register of lobbyists was required but said politicians need to "better manage this whole issue" in a way that "doesn't constrain people from getting their points across in parliament."
Lord Laird has resigned the Ulster Unionist whip pending an inquiry into allegations he broke parliamentary rules, party leader Mike Nesbitt said.
Having reviewed the video footage on the Daily Telegraph website, and other media reporting of Lord Laird's engagement with alleged lobbyists, I telephoned his home this morning and as a result he has relinquished the Party Whip, pending the outcome of the review of his behaviour that he has already requested of the relevant authorities at Westminster.
Speaking on Radio Five Live he said he though he was being asked to be a consultant for the fake company and said he had followed the Parliamentary Code of Conduct. Asked if he had done anything wrong he said:
Ulster Union Lord Laird has denied claims he breached parliamentary rules after The Sunday Times alleged he offered to act as a paid advocate for a fake lobbying firm. He was one of three peers implicated in a sting by the newspaper.
"In recent days I have been the subject of a scam operated by journalists masquerading as communications consultants. This has led to allegations that I have broken the rules of the House of Lords.
"I wish to make it clear that I did not agree to act as a paid advocate in any proceedings of the House nor did I accept payment or other incentive or reward in return for providing parliamentary advice or services.
"Shortly after the meeting, because it was so obviously a scam, we reported it to the appropriate authorities in the Lords.
"I have not broken any rules. However, I have referred the situation to the appropriate authorities and I will be making no further statement until I have received their ruling."