Michelle Chan, 29, said she felt “embarrassed” after she was told she could not stay inside Barber Barber, in Albion Place, on Sunday.
The company specialises in “gentleman’s barbering”, according to its website, and reports of a male-only policy have also been made about its Liverpool branch.
Miss Chan said she was asked to leave shortly before closing time on Sunday after she went in to wait after her brother Chris and boyfriend Daniel Williams had gone into the store for a cut without realising the policy was in place.
Miss Chan, who works in recruitment, said: “We were walking around and my brother and boyfriend both said they needed their hair cut.
“They’d never been there before so my brother went in first, then my boyfriend.
“[A staff member] spoke to my brother first, staying ‘Unfortunately this is a gentlemen’s barbershop, whoever’s not having a cut has to leave’.”
She said she went back in 15 minutes later and was again asked to leave, being told it was “gentlemen’s only”.
She said: “I sat in the street for like five minutes and I thought, that’s ridiculous. I went back in and they raised their voice.”
Miss Chan added: “It’s embarrassing because he said, ‘I really need you to leave the premises’, like I had done something wrong.”
A spokeswoman for Barber Barber said: “The waiting area within our store is reserved for customers waiting to receive a service.
"For anyone wishing to wait for customers, we provide vouchers for nearby coffee shops where they can wait in comfort and enjoy a drink.
"Our business is a walk-in service and queues deter walk-ins."