Submitting high-performing universities to full institutional quality reviews once a decade may not be enough to safeguard standards, David Willetts has conceded.
Speaking at the Quality Assurance Agency's annual conference, held in London on 25 June, the minister for universities and science said that reducing the frequency of full audits by the standards watchdog to once every 10 years would be an "extreme option".
His comments confirm a change of tack from the government's White Paper, which suggested that universities with reliable track records in quality assurance terms might be exempted completely from full QAA checks.
Under the current system, full institutional checks take place every six years, but it is now proposed that the interval varies between six and 10 years depending on universities' past performance in reviews.
The Higher Education Funding Council for England is currently consulting the sector on the new risk-based quality assurance regime, which is scheduled to take effect in 2013-14.
"We could not go to a system of zero audits," Mr Willetts told the QAA conference. "But the question was how frequent [they were]."
He added: "I think 10 years is an extreme option, but we will see what happens."
In its consultation, which closes on 31 July, Hefce also suggests that unscheduled university inspections could be triggered by poor student satisfaction scores and graduate employment data, plus low levels of professional accreditation for teaching staff.
Asked at the conference why the quality assurance system needed to be reformed, Mr Willetts said: "My view is there was not a sufficient risk-based trigger.
"There is some genuine scope for rebalancing [the system], which will make it more responsive."
But Shabana Mahmood, shadow minister for higher education, said she was wary of "fundamental changes to our sector...[brought in] under the radar".
"We need to maintain confidence in the quality of our sector so we can compete [internationally]," she added.
Ms Mahmood called for the government to draft a higher education bill to allow MPs to scrutinise the changes.
Speaking in an earlier panel discussion at the event, Roger King, visiting professor at the University of Bath School of Management, said the new regime could leave the QAA and the academy open to attack.
"Risk-based regulation might not detect a scandal waiting to happen and the government will come down like a ton of bricks on the sector," he said. "It would be very difficult for a risk-based regulator to say why it had taken decisions without becoming mired in a controversy that would run and run."