Taxing trusts as if they were companies and applying a new top marginal tax rate on incomes of more than $1 million would raise billions of dollars for the Commonwealth budget and alleviate pressure to slash welfare programs for the genuinely needy, the Greens have said.

The country's third political force has commissioned an updated independent costing of the two proposals originally put forward by the Parliamentary Budget Office, as an alternative to a raft of harsh spending cuts being considered by the Abbott government.

Another option: The Greens are suggesting a new income tax rate as an alternative to harsh spending cuts by the Abbott government. Credit:Alex Ellinghausen

The move has been calculated to illustrate the ways that Australia's rich and poor are being cast in the Abbott government's narrative of a budget emergency.

These measures have yet to be announced but speculation is rife in Canberra that the first Hockey budget could contain decisions to tighten eligibility for the age pension, make GP visits more expensive through the application of a co-payment by patients of $6, and even see a crackdown on eligibility for the Disability Support Pension.