Opposition Leader Bill Shorten will capitalise on Prime Minister Tony Abbott's absence overseas and launch a blitz on marginal seats to highlight broken promises in the budget that will push up the cost of living for families.

Mr Shorten has mocked Coalition MPs for sitting in their offices and hiding from scrutiny, saying if they don't want to sell the budget, ''we'll sell it for them''.

In a sign of Labor's growing confidence following the extraordinary budget backlash against the government, Mr Shorten will visit Liberal and Labor marginal seats in Melbourne and Sydney, with a trip to Brisbane being finalised, between Tuesday and Thursday.

The ALP is tight-lipped about the Opposition Leader will visit, but it is understood he will travel to western Sydney and outer-suburban Melbourne.

Mr Shorten said the Prime Minister's ''budget mess'' had not gone away simply because he had gone overseas.

''Coalition MPs can't just sit in their offices and hide from scrutiny, they need to hear what people really think about this unfair budget, and they need to pass the message on to Tony Abbott,'' he said.

''They should be telling the Prime Minister how much his budget will hurt their electorates, not staying quiet. If they go back to Canberra next week and don't speak out against the $7 GP tax and the pension cuts, their communities won't forgive them.

''If the Coalition doesn't want to sell their budget, we'll sell it for them. We'll be telling Australians about the new taxes, the cost of living increases and the savage cuts. And we'll be reminding people Tony Abbott lied to them before the election.''

Shadow treasurer Chris Bowen will head to Western Australia, health spokeswoman Catherine King will go to regional Victoria and other members of the shadow ministry are preparing to criss-cross the country to sharpen Labor's attack on the budget.

In western Sydney, Mr Shorten will meet ethnic leaders from Middle Eastern and Indian communities as well as local business owners to discuss the proposed winding back of the legal protections in the Racial Discrimination Act and cuts to multicultural grants.

Backbench Labor MPs have been told to get out into their electorates this week, with Parliament not sitting, and attend family and pensioners events, visit schools, hospitals and universities.

The MPs have been told to contact the local media in neighbouring seats held by Coalition MPs.