CANBERRA, May 31 - While public debate on the university package has largely been subsumed by the noise around schools funding, senators will focus on the nitty gritty of higher education first in a budget estimates hearing on Wednesday.

The government wants to impose a 2.5 per cent "efficiency dividend" on university teaching funding in 2018 and 2019, increase student fees by up to $3600 for a four-year degree, and drop the income threshold when graduates must start repaying HELP debts to $42,000.

It also wants to tie 7.5 per cent of university funding to performance measures including transparency of enrolment processes and student outcomes, although any funding that is cut from a poor-performing university will be given to better performers, not returned to the federal budget.

Labor, the Greens and independent senator Jacqui Lambie strongly oppose the changes.

Vice-chancellors unanimously oppose the funding cuts and fee hikes.

Senators on Wednesday will also get the chance to quiz the skills watchdog and department officials about changes to vocational student loans.

It's likely to include questions about support being provided to 15,000 students affected by the collapse of training provider Careers Australia after its federal funding was withdrawn.