Independent member for Murchison Ruth Forrest dismissed a threat by Premier Will Hodgman to repeal the legislation which has now passed after Speaker Sue Hickey voted with Labor and the Greens.

"The Tasmanian Law Reform Institute will look at the bill when it is enacted and see if there are any areas that need to be addressed," Ms Forrest said.

"It is disappointing that the scaremongering by the government continues.

"I'm not sure what areas the Premier has problems with.

"When a baby is born nothing changes and there is a process for changing gender on a birth certificate."

Ms Forrest said the legislation underwent extensive scrutiny.

Labor's legal spokeswoman Ella Haddad also rejected any move to repeal the legislation.

"The threat to repeal it is incredibly cruel to trans-gender and gender diverse Tasmanians," Ms Haddad said.

"What faith can they have in their government that has done everything it could to stall and try to defeat these changes?"

The Tasmanian Law Reform Institute will examine the legislation and review its interaction with other Tasmanian laws.

The TLRI is currently working on an issues paper which will be released for public comment in late May.

A final report will be publicly released in October and include any recommendations for "consequential amendments or policy reform".

Transforming Tasmania spokesperson, Martine Delaney, said she would be concerned if the government tried to repeal the legislation.

"I would worry if the Premier tried to repeal it - I wouldn't lie down and let that happen without a fight," Ms Delaney said.

"He needs to understand that it is not the government that passes legislation, it is the parliament that passes laws and both houses supported this legislation.

"It was the most scrutinised legislation to come before parliament in recent times."

The legislation allows 16-year-olds to change their registered gender via a statutory declaration without the permission of their parents.

It also removes the requirement for transgender people to have sexual reassignment surgery in order to have their new gender recognised.