Tory Party chairman Baroness Warsi was accused of fuelling Islamophobia after she claimed electoral fraud in Asian communities had cost the Conservatives at least three seats in the general election.

Labour MP Khalid Mahmood said he did not believe it was possible to commit fraud on such a scale in Westminster elections and he challenged her to produce the evidence to support her claims.

Lady Warsi told the New Statesman magazine there were “at least three seats where we lost, where we didn’t gain the seat, based on electoral fraud”.

She refused to identify the seats concerned but said the problems were “predominantly within the Asian community” and that Labour had been the beneficiary.

”I have to look back and say we didn’t do well in those communities, but was there something over and above that we could have done? Well, actually not, if there is going to be voter fraud,” she said.

In the same interview, Lady Warsi, who is herself a Muslim, attacked Islamophobia in the media, saying it was “the last socially acceptable form of bigotry in Briton today”.

Mr Mahmood, the MP for Birmingham Perry Barr, said in accusing Asian communities of fraud, she was simply adding to the anti-Islamic sentiment.

”If you read the article, what she is talking about in terms of Islamophobia, and I think that she is doing exactly the same thing,” he told BBC Radio 4’s The World at One.

”What she has done is open the door to which people can assume certain things, particularly about minority communities and the Muslim community.”

He said he did not believe it was possible for fraud to affect the outcome to such an extent in a general election.

”I can’t see that happening, I don’t think, on that large a scale in a parliamentary election where something in the region of 40,000 votes are cast,” he said.

Mr Mahmood said if Lady Warsi had any evidence to back up her allegations, she should take it to the appropriate authorities.

”She needs to substantiate that. She needs to give the evidence to the authorities and make sure it is investigated,” he said.

The Electoral Commission watchdog said it was not aware of any approach from Lady Warsi regarding the claims and that any such concerns should be taken to the police.

It will publish a joint report in January with the Association of Chief Police Officers setting out complaints made about the 2010 election and the outcome of them.

However a spokeswoman pointed out that the deadline for making an official appeal against results had passed without any action by the party.

Lady Warsi told the New Statesman that she had written to Deputy Prime Minister Nick Clegg, who is overseeing reform of the electoral system, to highlight the issue of fraud and voter disenfranchisement.