The Turnbull government has yet to woo the Greens in supporting either an increase in the Medicare levy or its new school funding model - two key components in last month's budget.
Greens Leader Richard Di Natale says the government needs to go back to the drawing board on both issues.
While he supports needs-based funding for schools, the government has come up with a weak compromise rather than pursuing an independent resourcing body as recommended under the original Gonski plan.
"We had Labor come in and basically make all these special deals for some of the richest schools who are deciding whether they build an equestrian centre or rowing sheds," Senator Di Natale told ABC television on Sunday.
"We have a government prepared to fix some of those problems with the formula but not put the money it needs."
On the 0.5 per cent increase in Medicare levy to help fully fund the national disability insurance scheme, Senator Di Natale said this was not the fairest way of raising revenue.
He said someone who negatively geared four or five properties and was able to reduce their taxable income would be paying less than someone earning $22,000.
"If the government wants to look at other ways of raising revenue so people on low incomes aren't facing a burden, we will look at that," he said.
If the Greens side with Labor in rejecting both proposals, the government will need the support from a fractious crossbench to pass the Senate.
