The mining tax will keep its present form as Prime Minister Julia Gillard insisted on Monday to "bring the legislation to Parliament exactly as we outlined," even as her deputy, Federal Treasurer Wayne Swan, earlier maintained that the new tax will spur more mining activities and deliver on its pledged benefits.

Speaking with reporters in Canberra, Ms Gillard said she remains committed with her vow of providing tax breaks to small businesses and that initiative will be made possible by the imminent passage of the minerals resource rent tax (MRRT).

The Senate is set to vote on the legislation Monday evening, with its approval almost a shoo-in despite the expected opposition from the Coalition.

The Australian Green Party has insisted on a number of amendments, including the likely extension of MRRT's coverage to gold and uranium from coal and iron ore but Ms Gillard, who had earlier won the backing of mining giants such as BHP Billiton, Rio Tinto and Xstrata for the mining tax, firmly rejected the revisions.

Nonetheless, Greens leader Bob Brown has reiterated his party's support for the bills, saying "we will be voting for it because the alternative is to raise nothing."

Senator Brown stressed too that minus the Greens proposals for the legislation, which were shot down by both the government and the Coalition, the new tax "fell way short of the mark."

"There some really important amendments to this tax which would make it better for all concerned if the Opposition were to join the Greens in supporting those amendments," Senator Brown was reported by the Australian Associated Press (AAP) as saying on Monday.

He reminded both Ms Gillard and Abbott that their actions would inevitably lead to financial black holes that would impact on crucial government programs.

"They are creating their own black holes when it comes to funding disability, education, the need for further public infrastructure like high-speed rail," Senator Brown said.

However, Ms Gillard is optimistic that the MRRT will in fact support her plans of delivering a budget surplus by 2013 without weighing down on important government spending.

"It's in the interests of the Australian economy and the Australian people that we return the budget to surplus ... and what you should expect is for the government to take the prudent approach it has to government spending," Ms Gillard said.

In his regular economic note, Swan asserted that the MRRT will provide the funds that would assist small businesses struggling in an economic environment that he admitted was largely created by the ongoing mining boom.

"(By) increasing superannuation, the MRRT will also help businesses, particularly small businesses outside the fast lane of the resource sector," Swan said as reported by Bloomberg.

The Treasurer also rejected suggestions that the mining tax could deter the inflow of more mining projects due to higher levies that firms would face in Australia as warned by Opposition Leader Tony Abbot in his attempts to block the passage of the legislation.

"We all know these resources can only be sold once ... that is why the government is committed to locking in the benefits of the mining boom and ensuring Australians receive a fair return," Swan reminded on his note.