Nigel Farage has pledged that Ukip would impose an "ethical" visa system if the party took power, as he ruled out any "arbitrary targets" on immigration.
The eurosceptic leader, who will today unveil his party's immigration policy, wrote in the Telegraph that his party did not want to "stigmatise" immigrants.
However, he wrote that he would propose a migration control commission and abolish rules discriminating between EU and non-EU nationals.
Farage added that Ukip's proposals would include a points-based system for visas, as seen in Australia, with the aim to bring down migration levels that were "unsustainable, unfair and unethical".
He also said there would be a five-year block on visas for unskilled workers, barring them from claiming benefits during that time.
Nigel Farage has hinted there is still a chance that another Conservative MP could defect to Ukip before the General Election.
Asked in an interview with the Sunday Telegraph (£) whether he was in discussions with any Tory MPs, Farage said: "The last time I spoke about this I said I would be surprised if there were not more.
"There is one conversation we are still having. But do you know what - it is not very relevant now. Last year it was a big deal."
Unlike Douglas Carswell and Mark Reckless - who both triggered and won by-elections - a Tory jumping ship now would be likely to hold on to their seat until the General Election in May.
Douglas Carswell is expected to urge Ukip activists to break the "Tory-Labour power cartel" in May's General Election.
The Conservative defector, who triggered and won a by-election in his Clacton-on-Sea seat, will set out his blueprint for political reform and reconnecting with voters at the Ukip spring conference later today.
Mr Carswell is the highest-profile speaker on the second day of the Ukip conference at the Winter Gardens in Margate, Kent.
Britain's sewerage system is struggling to cope with the influx of migrants, a senior Ukip figure has warned.
Immigration spokesman Steven Woolfe raised the issue as he listed elements of infrastructure that were under pressure because of immigration during his speech to the party's pre-election conference.
Mr Woolfe insisted the public did not care about "colour of skin or race or creed".
He added: "What they are concerned about is that our eye has been taken off the ball for nearly a generation," he told the audience in Margate.
"Schools are now full, hospitals are troubled, healthcare - it is very difficult to be seen in many areas of this country.
"Roads need to be built, we need to look at the way we feed ourselves because of our growing population.
"What about our water and sewage systems? All of these matter."
Ukip leader Nigel Farage claimed the party is on its way to winning the Conservative seat of Thanet South as polls showed him holding a wide margin over his opponents.
Mr Farage also accused Labour and the Conservatives of indulging in negative campaigning and insisted his party would focus "on the politics of hope and inspiration".
He added that immigration was the topic dominating the election and Ukip was the only party which could regain control of Britain's borders.
Mr Farage was addressing the party's Spring conference in Margate.
Ukip remains the party most trusted to control immigration despite more people seeing them as racist, a ComRes/ITV News poll has found.Read the full story ›
The chair of Ukip's lesbian, gay, bisexual and transgender (LGBT) supporters has left the party, citing "dissatisfaction at the failure of the leadership to set a gay-friendly tone".
Last night I stepped down as Chairman of LGBT* in UKIP and gave up my membership of #ukip. I'll remain unaffiliated...for now ;-)
@r4vi very simply, I found that I couldn't defend the party or convincingly campaign for it any more.
"It became increasingly difficult for me to argue for a non-Classical Liberal manifesto," Booker added.
He later told PinkNews magazine he had resigned "due to disillusionment of policy direction and dissatisfaction at the failure of the leadership to set a gay-friendly tone".
Nigel Farage has said his plans to tackle "health tourism" would not turn the NHS into an American-style health system.
The Ukip leader said: "We are a civil country and we are civil people. There may be people who come in without medical insurance, such as genuine refugees.
"The idea that someone who was in trouble would not receive treatment is not what we're saying here."
Nigel Farage has said he would make it a condition for people coming into the UK to have health insurance if they want to seek medical treatment here.
Outlining Ukip's policies on the NHS, the party leader said this would apply to those entering on a visa or work permit "as we would do if we were abroad".
Dubbed "health tourism", the cost of paying for overseas patients to undergo healthcare on the NHS is estimated to cost up to £2 billion a year.
Farage added he was committed to keeping the NHS free and pledged to abolish hospital car parking charges if elected.