GREENS leader Bob Brown will today fire a substantial warning shot before the introduction of the mining tax package, declaring banks don't deserve a $4 billion tax break, but small business does.

The Greens will today make it clear they want the big banks carved out of the 1 per cent corporate tax cut planned as part of the mining tax package, pitching a 5 per cent tax cut for small business instead.

Senator Bob Brown. Credit:Andrew Meares

The Gillard government's intention has been to use revenue from the mining tax proposal to fund a 1 per cent cut in the corporate tax rate, tax relief for small business, increased superannuation contributions and new infrastructure. But with legislation for the troubled package finally reaching Parliament next week, crossbench kingmaker Tony Windsor has also thrown a last-minute spanner in the works.

Mr Windsor yesterday linked his support for the mining tax package to a rolling fight between farmers and gas companies over contentious coal seam gas exploration.