He has also demanded assurances that none of the lawyers who attended would be promoted as a result.
It is the latest allegation of sleaze to hit Labour following the Hinduja passport row that brought down Northern Ireland Secretary Peter Mandelson .
He told the BBC that the office of lord chancellor had always combined political and judicial roles but these were kept completely separate.
"He acts in this matter as a politician. The Tories need to get back to the real issues - jobs, health, education, - where their policies are bankrupt," he said.
Lord Irvine was an "exemplary politician and an exemplary lawyer".
The lord chancellor, who as head of the judiciary has the power to appoint QCs and judges, sent letters to solicitors and barristers inviting them to a party fund-raising dinner he was hosting at a London nightclub.
Breach of trust?
Tory chairman Michael Ancram accused him of breaching the trust placed in him and bringing the integrity of his office into question.
At the dinner, Lord Irvine's letter explained, the lawyers would be asked to pledge at least £200 "in order to secure a second term for Labour".
The event on 7 February included Cherie Blair as guest of honour and Attorney General Lord Williams of Mostyn as the guest speaker.
In a letter of protest to Mr Blair, the Conservative chairman called on him to review Lord Irvine's position.
Mr Ancram demanded Labour publish the names of those lawyers who attended the fundraising meal and the amount they had donated to party funds.
He has also demanded assurances that none of the lawyers who attended would be promoted as a result.
"In order to protect the integrity of the office of lord chancellor, there is in my view no other option but for Lord Irvine to resign," said Mr Ancram.
"I find it very difficult to see how a lord chancellor can claim to be independent when he is going out effectively as the begging boy for Labour."
But Downing Street has insisted that Lord Irvine - a close friend and ally of Mr Blair - was not guilty of any wrongdoing and dismissed the calls for him to resign.
'Diversion tactic'
The prime minister's official spokesman accused the Tories of using the story to divert attention from real political issues.
"This is exactly the sort of issue that the Opposition and parts of the media prefer to focus on as it avoids real debate on policy and the issues that matter to people in this country," he said.
"The prime minister will treat calls for the lord chancellor's resignation with the contempt they deserve."
A Labour spokesman defended Lord Irvine by saying he was not told how much anyone attending the dinner actually donated to the party.
But former Tory home secretary Michael Howard described Lord Irvine's action as a "fundamental corruption" of his office and added his voice to calls for the lord chancellor to resign.
Liberal Democrat peer Lord Lester called for the lord chancellor's role to be reformed.
"It says in the Bible that no man should serve two masters. The lord chancellor serves two if not three... and he cannot go on wearing all these different hats.
"Once again he has confused the distinct roles."
On two previous similar fund-raising occasions, money had been raised through ticket sales.
'Storm in a teacup'
This year the dinner was free but, in his invitation to Labour-supporting lawyers, Lord Irvine wrote that they would be making an appeal on the evening for the party's general election fund.
Malcolm Fowler, of the Law Society, described the affair as a storm in a teacup.
"I wouldn't really have thought that this is much of a farce, it's certainly not a hanging offence."