The face veil stops Muslim women taking their "full role" in society, a candidate for the Labour deputy leadership has said.
Harriet Harman, the constitutional affairs minister, backed Jack Straw's comments about the niqab and said she did not think women should wear it at all if they wanted equality with men.
"How can you if you can't get a driving licence or a passport? The veil is an obstacle to women's participation, on equal terms, in society," she told the New Statesman.
Ms Harman said Mr Straw's intervention "would have been better if he was a Muslim woman", but noted this option presented difficulties. "How can you stand as an MP when men's faces are on posters and voters can't see yours?" she asked.
The MP for Camberwell and Peckham is the only woman who has put her name forward for John Prescott's job so far, alongside Northern Ireland secretary Peter Hain and backbencher Jon Cruddas.
Mr Straw and education secretary Alan Johnson are also strong potential candidates, but Ms Harman believes that an all-male leadership of Labour would not send the right message to voters.
Of the House of Commons, she noted: "There is still a lot of testosteronal stuff - it's still male dominated. Women have changed things, and we're light years ahead of the Tories, but the culture still has a long way to go."
Ms Harman is a strong campaigner on women's rights, and one of her suggestions as deputy leader would be to force employers to explain why employees should not adapt their working hours around their children, rather than vice versa.
"Decisions that should be being made by parents are being made, by default, by employers. We have to put the power back. You don't do it by pointing at good practice," she said.
She told the magazine: "You have to shift the burden of proof. The onus would be on employers to prove why it [a work schedule chosen by a parent] wasn't possible."
Ms Harman is a strong ally of Gordon Brown and has backed him to be Tony Blair's successor. Asked whether he would support her plans for more flexible working, she said: "I feel unlikely to be disappointed in this - why would he not understand?"