Prime Minister Malcolm Turnbull has declared budget repair the "massive moral challenge" of the new Parliament, challenging Labor, the Greens and the crossbench to tackle the nation's ballooning debt "head-on" while echoing Kevin Rudd's stark warning about climate change a decade ago.

And Fairfax Media has obtained a leaked copy of a "backbenchers brief" that sets out the details of the so-called omnibus savings bill, which largely contains measures that Labor agreed to, or indicated it could agree to, during the election campaign.

The leaked document reveals the omnibus bill is designed to save $6.1 billion over four years and includes 24 measures - up from the 21 that had initially been foreshadowed.

As MPs returned to Parliament on Monday after a four-month break, the Coalition partyroom meeting signed off on 26 different pieces of legislation, including the omnibus bill, that will be presented to the Parliament.