National's leader, John Key, says there will be "some modest changes" to the KiwiSaver scheme if his party wins the election.

Mr Key would not give any details today when he was questioned on TV One's Breakfast programme but he said nothing radical would be done.

More than 700,000 people have signed up to the scheme, which was introduced by Finance Minister Michael Cullen.

National's Taranaki-King Country MP Shane Ardern caused a stir yesterday by talking about it to a local community paper.

Dr Cullen, quoting from the report, said Mr Ardern had said the scheme needed adjusting "from the employers' contribution angle".

Under the scheme, employers contribute to the savings of their employees and are compensated by a tax credit.

The Government has always held suspicions that a National government would reduce employer contributions.

Mr Ardern has said he was misquoted.

Mr Key said Mr Ardern was not involved in KiwiSaver policy development.

"There won't be radical changes," he said.

"There will be some modest changes to KiwiSaver.

"We will announce that pretty soon."