Westpac employees will have access to up to four weeks of paid leave and a year of unpaid leave to make a gender transition under a new wages and conditions agreement.

The new enterprise bargaining agreement also doubles paid domestic violence support leave from 10 to 20 days. Aboriginal and Torres Strait Islander employees will be given access to three days for "Sorry Business".

Compassionate leave has been increased to three days per occasion and a 3.25 per cent pay rise will be given to employees that earn up to $82,500.

Finance Sector Union national assistant secretary Nathan Rees said Westpac was the first bank to have introduced transgender leave as far as he was aware.

"It is a positive step," he said.