The 2018 Wellingtonian of the Year has apologised after describing an anti-sex self-identification group as "whores" on Twitter.

Last August, a Government select committee recommended simplifying the process by which Kiwis can change the gender marker on their birth certificates.

It set off a fiery debate, in which prominent New Zealand feminists have clashed with transgender activists over the issues of biological sex and self-identification.

Top lawyer Steph Dyhrberg waded into the argument on the side of transgender activists.

"I'm furious. These anti-trans whores do not speak for women. How dare they," she tweeted. "Wish they would take up knitting."