I would use this as an opportunity to remind everybody that absolutely no media or campaign opportunities are under way

Spokesman for Ken Clarke

But he said that Labour's experiment with women-only shortlists had not been a success - resulting in MPs who had not performed well.

His comments were dismissed as "patronising nonsense" by one Labour MP.

The publication of Mr Duncan Smith's remarks prompted a warning from rival Ken Clarke's campaign team who reminded the right-winger that a two week campaign truce had come into force on Wednesday.

A spokesman for Mr Clarke said: "I would use this as an opportunity to remind everybody that absolutely no media or campaign opportunities are under way."

Although the interview was conducted on Monday - ahead of the campaign truce being called - but only published on Wednesday.

In the interview with epolitix.com, Mr Duncan Smith said: "All-women shortlists have not been a success for Labour, because instead of getting people who are high quality, what we've actually got in is people who haven't really performed as politicians for the Labour party.

Mr Duncan Smith says the party needs to broaden its appeal

"So we need to learn a lesson from that, whilst making sure we certainly do get many more women and members from ethnic minorities into winnable seats."

Mr Duncan Smith also conceded that many people regarded the Tories as a party that represented only a small group in society and indicated that extending the appeal of the party to people of all backgrounds was key in their fightback from defeat.

The message to the public had to be that "it doesn't matter what your colour, your creed, whether you're male, female, whatever," he said.

Come and join

"We simply say 'come along and join the Conservative Party'. And we have to now make the party look more like the country that it's going to be elected to govern."

Mr Duncan Smith's comments echoed those he made in response to a survey conducted by the Conservative Christian Fellowship.

"After consulting prominent women in the party, I have come to the view that we should not adopt Labour's all-women shortlists," he said

"I would consult with women and ethnic minorities in the party to see how best we can overcome the barriers that exist."

Shortlists were used to select 35 women Labour MPs ahead of the 1997 general election although the system has since been jettisoned after an industrial tribunal ruled it broke existing sex discrimination legislation.

The government has since said it will legislate to allow the shortlists.

Junior Housing Minister Sally Keeble said Mr Duncan Smith's comments showed the "total vacuousness" of today's Tory party.

"It is a measure of their total despair and the total failure of the Conservative party to get a parliamentary party that reflects the country.

"I should have thought that potential leaders of the party would have something relevant to say and not be fighting yesterday's battles.

"I just think that it shows the depth of the problem that the Conservative Party has got in their inability to modernise," she said.

Fiona Mactaggart, Labour MP for Slough, said Mr Duncan Smith's criticisms were "utterly ridiculous".

"The evidence is that there are some very strong MPs who were elected through all women shortlists," she said.

"It is patronising nonsense, frankly, and does not offer anything to women who have suffered from the gross sexism in the selection process of the Conservative Party."