Govt tax crackdown "watered down": Shorten

The government's planned company tax evasion crackdown is "political camouflage" designed to claw back credibility, federal opposition leader Bill Shorten says.

Mr Shorten said the plans to close company tax loopholes merely enact reforms announced by Labor - but in a watered-down state.

Treasurer Joe Hockey this week said the government would legislate to close loopholes that companies use to avoid their tax obligations and create a level playing field for taxation of businesses.

Mr Hockey said large multinationals should face the same tax environment as small businesses.

Under the proposed changes, the amount of debt a multinational firm based in Australia can have on its books will be lowered.

But Mr Shorten said the government's changes to Labor's provisions meant about $1.1 billion in revenue would be foregone.

"The Treasurer's claim that the government will be legislating to close multinational tax loop holes is not a bold statement - it is nothing more than political camouflage," Mr Shorten told an economic forum in Melbourne on Friday.

"We introduced business tax integrity measures that are now worth more than $5.3 billion.

"Yet not once, but twice, the Abbott government has moved to water down these provisions."

He said because the changes were based on a Labor policy from 2013/2014, the figures had already been included in forward estimates so there was no additional revenue gained.

"After delivering a budget that has targeted pensioners, families, students, carers, veterans and the sick - the government needs something to balance the credibility ledger," Mr Shorten said.

The OECD, through the G20 under the presidency of Australia, is currently working on a framework to prevent tax avoidance by multinationals.

Its plans will be taken to the G20 Brisbane summit in November.

Mr Hockey said he would introduce the new legislation into parliament this month.