Labour have launched a vicious assault on Ukip by claiming the Eurosceptic party is led by "Neanderthal sexists".
Deputy leader Harriet Harman warned women to steer clear of Nigel Farage's party and argued that Ukip tolerate "appalling" anti-female remarks.
"It's a backwards party run by dinosaurs who clearly expect men to be running the show and women to be obeying them," Harman told The Daily Mail.
"It's clear from their policies and what they say, and what they do that Ukip is bad for women.
She added: "It's not just the Neanderthal sexist comments, and their overwhelmingly male team of candidates – their policies show no recognition that half the people in this country are women and that women expect, and are entitled, to be treated on equal terms to men. It's a party frozen in time."
The comments are the latest attempt from Ed Miliband's party to counter Ukip's rise as the party threatens to steal votes from Labour at the general election.
But Suzanne Evans, Ukip's deputy chairman and newly appointed policy chief, hit back at Harman and claimed the senior Labour MP had launched a "vicious and completely uncalled for" outburst.
"I'm beginning to see why even her own colleagues call her Harpie Harman," she said.
"I don't believe she's ever met Farage, but if she had, and if she'd worked with him, as I do, she'd find he's extremely knowledgeable, great company, has a wonderful sense of humour and is an all-round decent chap.
"He no more believes women are worth less than I do. His supposed 'anti-women' comments have been spun out of all proportion.
"Ukip is not sexist. That's utter rubbish. If Ukip was sexist, I wouldn't be deputy chairman and handed the huge responsiblity of delivering the general election manifesto.
Evans added: "We wouldn't have seven female MEPs, all of them selected to stand by our members. And we certainly wouldn't have more frontbench spokeswomen than any other national party.
"Like other women in Ukip, I can be confident I'm doing the job I'm doing because I was chosen to do it on merit, not because of ridiculous and demeaning quotas that mean I tick the right equality box. That's what Labour's policies have reduced women to and it infuriates me."
IBTimes UK spoke to Evans on the issue last year when the deputy chairman admitted that Ukip had "shied away" from looking at women's issues and policies.
"We have this fundamental principle that everybody should be treated equally," Evans said.
"It amazes me because we do have this actual focus on equality, but, because it's not the sort of politically correct tick-box type of equality, we seem to be penalised for it. It completely baffles me."
Evans' remarks came after a poll from Survation for the Daily Mirror revealed that most men would vote for Ukip.
But the survey also revealed that female voters preferred Labour and the Conservatives over Nigel Farage's party.