Lawyers for four women have threatened controversial influencer Andrew Tate with a lawsuit in the English courts over allegations of sexual assault.

Former kickboxer Tate – who is under house arrest in Romania after having been held over alleged human trafficking and rape – was served with legal papers by British law firm McCue Jury and Partners.

A statement from the law firm on Wednesday described the women's allegations "including violent rapes, serious physical assault, and controlling and coercive behaviour."

It said the women had "put Tate on notice that, depending on his response, legal proceedings will be initiated against him at the High Court in London in the coming weeks", the firm said.

The women, now in their late twenties and early thirties, say the offences took place between 2013-2016, when Tate was based in the UK.

"Andrew Tate categorically denies the veracity of the accusations brought by the lawyers of the anonymous women in the UK," a spokesperson for Tate said in a statement.

Three of the women had filed criminal complaints that the UK authorities had decided to reject, the statement added.

"What new evidence could have appeared nine years later that would overturn the court's decision?"

Romanian police arrested Tate, 36, and his brother Tristan, 34, late last year.

A Romanian court placed them under house arrest at the end of March after three months of preventive detention on accusations of human trafficking and rape.

They deny all the accusations. (AFP)