University leaders say there is a huge amount of uncertainty around what to tell prospective students who face potential changes to course fees part-way through their degrees.
Universities across Australia are currently in the middle of Open Day season for students planning further study in 2015.
The Government has introduced legislation into parliament to deregulate fees from the start of 2016 but is facing an uphill battle to get its higher education reforms through the Senate.
The reforms also propose a 20 per cent cut in course funding and an increase of interest rates on student loans.
University of Sydney vice chancellor Michael Spence said students would not be targeted with high costs but cannot say how much universities will charge until the reforms are finalised.
"The purpose is not to gouge money out of students. The purpose is to be able to continue to provide a high quality education and therefore very dramatic fee increases are unlikely," he said.
"There is a huge amount of uncertainty and that for me is why the timing is quite important.
"If this is going to happen we have to get it to happen as quickly as possible so we can give certainty to parents and students and universities for that matter."
Australian Catholic University vice chancellor Greg Craven said: "We're telling them the situation is quite fluid and it's hard to know exactly what the fees might be".
"I can certainly guarantee they won't suffer enormous fee hikes," he said.
ACU attracts large number of nursing and teaching students who are often the first in their families to go to university and are often from low socio economic backgrounds.
Professor Craven reacted angrily to suggestions the country's top universities might scrap nursing schools which could attract lower fees than other courses.
"The present bill is very careful to make sure that nursing and education is cut by less than other areas," he said.
"It is imperative that that is maintained. There are some other universities that would like that to be changed. That must not change if we want schools and hospitals.
"It shows a priority that says perhaps money is more important than producing the professions of care. We clearly do not take that view and would be most alarmed if that type of financial view was to triumph over public interest."Expected spike in 2015 enrolments
There are suggestions the proposed higher education reforms could lead to a spike in enrolments next year.
Some year 12 students are being encouraged not to take a gap year in 2015 and go straight onto further study ahead of expected higher prices for some courses in 2016.
Dr Spence said the UK experience shows there was a surge in enrolments before course prices went up with many students deferring their gap year until after graduation rather than taking it between school and university.
He was reluctant to offer his own advice but Dr Spence said he would not discourage young people from taking a break in 2015.
He said it would be a "real pity if someone had plans for next year and decided to defer them".
"It's a very difficult decision ... I can say our commitment is to make education affordable whether you start in 2015, 16 or 17," he said.
Most in the higher education sector support fee deregulation to make up the shortfall in government funding and reduce the reliance on fees from foreign students.
Education Minister Christopher Pyne wants the bill passed by the end of year to give universities enough time to prepare for the changes but is facing strong opposition to the reforms in the Senate.