A MELBOURNE cafe that caused a social media storm after charging men a tax and seating women first insists it has had a stack of support.

And not just from the girls.

Handsome Her, a vegan cafe in Brunswick, said it was charging men 18 per cent more in a bid to address the gender pay gap.

The cafe, which clearly advertises its rules on a chalk board, explained men will be charged the premium - and the gap donated to women's services.

However co-owner Alex O'Brien told Seven News the surcharge, which is in place one week out of every month, wasn't compulsory.

She also said none had so far refused to pay it and in a Facebook post overnight said the idea has been well supported overall.

"If people aren't comfortable paying it or if men don't want to pay it, we're not going to kick them out the door," she said.

"It's just a good opportunity to do some good."

The idea has caused a mixed reaction on social media, with some supporting the concept.

Writing on its Facebook page overnight, the cafe insisted it was jam-packed with customers over the past few days who have supported the cause.

It also insisted it wasn't just women who were backing the idea.

"We've had men travel across town to visit us and pay 'the man tax' and throw some extra in the donation jar - guys, you're pretty neat," the post read.

The cafe also thanked its staff who have taken it all in its stride.

"It's not every day that your boss pulls you into her fire-pit of feminism and you have to quickly become warriors and defend where you work and what you do on a level that others never do," the post continued.

"You have not only been incredibly strong, proud and supportive, but nurturing and protective as well."