The battle to pass the Turnbull government's $144 billion personal income tax cuts has pivoted toward gender, with Labor labelling the final stage of the cuts unfair to women and Treasurer Scott Morrison rejecting a "pink and blue" tax system.

A month out from the Coalition's deadline to pass the largest personal tax cuts in Australian history, Labor has signalled it is ready to pit male high-income earners against female workers in the struggle for a greater share of the pie.

New figures released on Wednesday by the Parliamentary Budget Office show the final stage of the personal income tax plan will give Australian men a $30 billion tax break by 2028, compared to $11 billion for women.

Labor - who commissioned the Budget Office analysis - supports the second stage of the cuts, which give a tax cut to men of $49 billion compared to $31 billion for women, while the first stage of the cuts targeted at low income earners delivers a relatively equal share between the genders.