Wearing a full face veil harms women's participation in society and effectively bars them from becoming an MP, minister Harriet Harman has said.
Ms Harman says full veils are an obstacle to women's participation
Ms Harman, who is standing for Labour's deputy leadership, said: "How can you stand as an MP when men's faces are on posters, and voters can't see yours?"
"If you want equality, you have to be in society, not hidden away from it," she told the New Stateman magazine.
"The veil is an obstacle to women's participation on equal terms."
The constitutional affiars minister was speaking the week after Jack Straw sparked controversy when he said he would prefer Muslim women not to wear veils which cover the face.
Race equality boss Trevor Phillips said the comments were "completely right".
Mr Phillips, who heads the Commission for Racial Equality, said Mr Straw had the right to ask a woman to remove her veil at constituency meetings, and the woman had the right to refuse.
The Commons leader's remarks prompted much debate and were criticised by some Muslim groups.
"This is not a matter of public policy, it's a question of social etiquette and manners," Mr Phillips said.
Mr Straw, whose Blackburn constituency is about 30% Muslim, said he thought community relations were not improved by women wearing veils covering their faces, as they were "a visible statement of separation".
He said he now asked women to remove full-face veils when they come to meet him at his regular constituency surgery.
Mr Phillips said: "I think it's perfectly reasonable for him to say 'would you mind not making me feel uncomfortable' in this particular case - as long as it's understood the answer to that can be 'no'."
"Whether there should be social pressure to make the wearing of the veil unacceptable is, in my view, a separate question to that," he told the House of Commons Education and Skills Committee.
Veils in schools
"I go with those that say this has also got to be a matter for negotiation - it can't be prescriptive. You can't tell people what to wear."
Both Prime Minister Tony Blair and Chancellor Gordon Brown have backed Mr Straw for raising the debate. But the Islamic Human Rights Commission said he was selectively discriminating.
Mr Phillips was also asked about whether full-face veils should be allowed in the classroom, where face to face communication was important.
He told MPs it was not a decision that should be left to the teacher.
"If that's raised it should be as a matter of school policy," he said.
"If I were the head teacher in that school, I would probably say that veils should not be worn in the classroom."