Labor has pledged to return $2 billion to the budget by cracking down on tax avoidance by overseas mega-companies.

In its first major policy announcement in opposition, Labor has detailed how it will close loopholes to stop billions of dollars of tax bleeding offshore.

On Monday morning, Shadow Assistant Treasurer Andrew Leigh summarised the plan, accusing the Abbott government of ‘giving money back to the big end of town’.

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“This is an issue that many around the world have been concerned with – whether it’s the OECD, the G20, or even the Australian Tax Office. But the Abbott Government has dropped the ball,” Mr Leigh said.

“Labor will take a fairer approach, one that ensures a level playing field for businesses and a fair deal for Australian taxpayers.

“Meanwhile the Coalition, at every turn, is giving money back to the big end of town while slugging pensioners and families and making life harder for other Australians.”

The policy seemed to Labor’s response to repeated calls from the Prime Minister for the party to outline how it would return the budget to surplus, instead of simply ‘sabotaging’ Mr Abbott’s proposals.

The tax package, which has been costed by the independent Parliamentary Budget Office, would boost the budget by $1.9 billion over four years. A key measure would be reducing the amount of debt against which overseas companies can offset their profits.

Shadow Treasurer Chris Bowen said the announcement was an “opening salvo in a year of ideas”.

“If this government chooses to take up this option in their budget, regardless of whichever member of the government releases the budget, they will do so with our bipartisan support,” Mr Bowden said.

“If they don’t, then this announcement today is the blueprint for Labor’s approach in office.”

Mr Bowen said the package had been formulated in consultation with OECD papers, academia, the private sector and former government officials.

Tax avoidance by multinational companies has become a major issue in many countries because of the HSBC scandal.

Leaked documents from the bank’s Swiss division revealed that it had deliberately offered to help rich clients avoid tax.

—with AAP.