A plan to restrict older people's access to student loans has sparked calls of age discrimination, with the Human Rights Commission saying it could breach human rights law.

The Government has signalled it would restrict living cost loans to people aged over 55 in Thursday's budget, as part of a broader push to cut costs in the student loan scheme.

The move could save about $10 million a year.

The Human Rights Commission today said it would be concerned about any arbitrary age-related policy that restricted the ability of students to up-skill and retrain.

The commission's Equal Employment Opportunities Commissioner, Judy McGregor, said such a policy would potentially be unlawful discrimination under the Human Rights Act.

The Human Rights Act and the Bill of Rights Act make it illegal to refuse people goods and services on the basis of their age.

Tertiary Education Minister Steven Joyce said he had sought advice from officials and was satisfied the change was consistent with the Bill of Rights Act.

The difficulty with loaning to older people was that as they advanced in age, the likelihood they would repay their loans from income declined.

"We have an up to 70 percent write-off of those loans made to over 55s," Mr Joyce said.

"We would still look to retain loans for fees, it would be things like living costs that we would be concerned about."

But Dr McGregor urged the Government to explore non-discriminatory ways to recover student loan debts.

She said labour force data suggested the number of people in the workforce aged over 65 was climbing, which meant students over 55 would have more time to repay student loans.

Students aged over 55 were often women seeking a second chance at tertiary education or people seeking to retrain following redundancy.

Green Party tertiary education spokesman Gareth Hughes said refusing loans to older people was unfair and "a clear-cut case of age discrimination".

He said the move could expose the Government to legal action on the basis of discrimination.

"It would be much smarter to abandon this discriminatory policy than to wade into a complex legal minefield trying to justify that discrimination."

Greypower president Roy Reid said the move was a short-sighted exercise that targeted the elderly and could have serious repercussions in the future.

"The Government should explain why it should discriminate on the basis of age for no real reason apart from cost cutting."

New Zealand Union of Students' Associations co-president David Do said everyone could contribute to an innovative and highly skilled society, no matter whether they were young or old.

"Shutting out older students for no other reason than to cut costs is discriminatory and unfair," he said.

If the proposed changes were inconsistent with the Bill of Rights Act, it would be the Attorney-General's job to bring that to the attention of Parliament.

Attorney-General Chris Finlayson said he probably held the record for issuing such reports, compared with previous attorneys-general.

"I'll look at the bill when it comes before me, as I do in my capacity as Attorney-General, and give you my view then," he said.