But one healthcare industry body says politicians on both sides are locked in a funding "arms race" and trying to buy votes.

Prime Minister Scott Morrison and Health Minister Greg Hunt announced the funding boost at Mount Druitt Hospital in Sydney on Sunday, saying it would result in better diagnosis and treatment.

"MRIs are about saving lives and protecting lives," Mr Hunt said.

"Here at Mount Druitt they're already being used in cancer diagnosis or stroke detection."

Mr Hunt said ten licenses, selected due to their high need, would be issued from November 1.

The remaining 20 licenses would be open to expressions of interest from hospitals from Monday this week and operational from March next year.

Mr Morrison and Mr Hunt denied a Labor commitment to MRI funding, made on Saturday, pushed the government to make their own announcement.

"Our process to do this has been going for some time," Mr Morrison said.

Mr Hunt said the ALP figures were 50 per cent short of what was required and called on Mr Shorten to explain the "black hole" in his numbers.

The Australian Diagnostic Imaging Association called the funding "political window dressing" that did nothing to make the scans more affordable for Australians, who face out-of-pocket costs averaging $100 for radiology services.

"In Australia we restrict access to (MRI diagnosis) and, at every election, we see the major parties exchange MRI licences for votes," President Siavash Es'haghi said in a statement on Sunday.

"So, if you can't afford access to services like x-rays and ultrasounds, announcements around more MRI licences is going to do nothing to reduce your hip-pocket pain."

Dr Es'haghi called for an increase in Medicare rebates to help patients access medical scans.

Australian Associated Press