The platform does not resile from the party's core beliefs and positions, but like the main parties' manifestos it now presents them largely as ''aims'' and ''principles'' with fewer explicit policy measures.

After a year in which Labor figures have attacked the Greens as ''loopy'' and ''extremists'' who ''threaten democracy'', the new platform gives the federal elected MPs - nine senators and one lower house MP - more flexibility in negotiating legislation when holding the balance of power.

But it also makes it harder for opponents to attack or ridicule the party over specific policies.

For example, the new platform no longer specifies the Greens want to abolish the 30 per cent private health insurance rebate, but rather talks about ''redirecting funding from subsidising private health insurance towards direct public provision''.

And it no longer calls for a freeze on Commonwealth funding to private schools, but rather states that funding should be based on school need and that money not provided to the very wealthiest schools be instead given to the public sector.

The new platform was agreed at the party's November national conference and has now been approved by all the party's state branches.

It still makes clear the Greens want to increase the marginal tax rate for people earning more than $1 million, but no longer specifies that it should be put up to 50 per cent.

It advocates increasing the minerals resource rent tax and applying it to more commodities, but no longer proposes an increase in the company tax rate to 33 per cent.

It says the Greens want tax reform that improves housing affordability by no longer rewarding speculation, but it doesn't specifically call for an end to the concessional arrangements for the capital gains tax.

And - removing one of the critics' favourite lines of attack - it no longer specifies that the Greens support death duties or an ''estate tax''.

The Greens have had disappointing results in several recent elections, including the ACT poll when they lost three of the four seats they had held in the territory assembly.

Founder and long term leader Bob Brown retired this year and the new leader, Christine Milne, has sought to appeal to new constituencies, including rural voters and small businesses. But the Greens are attracting about 10 per cent of the national vote in most major opinion polls, compared with the almost 12 per cent they achieved at the 2010 federal election.

The party has begun a national fund-raising effort through microdonations to build a $3 million war chest for the federal election year.

Coalition Senate Leader Eric Abetz said the Greens were trying to hid their ''extreme impulses'' but this would fail.

''The Greens will always be ’watermelons’ - Green on the outside and red inside - no matter how they cloak their policies,'' Senator Abetz said.

''The Greens need to actually repudiate their extremist policies before people will believe they’ve changed.  Deciding simply not to talk about them simply will not wash.''

Labor minister Anthony Albanese said this year that if the Greens ''stood on their real platform, they would be struggling to get to 3 per cent of the electorate''. AWU national secretary Paul Howes said they were ''loopy'' and were extremists who threatened Australia's democracy.

with Dan Harrison