Gaps will rise if bulk-billing ditched: Duckett

GPs will start charging patients $25 co-payments if the government forces them to ditch bulk-billing, a leading health economist has claimed.

The warning from Professor Stephen Duckett (pictured) follows Thursday's release of the National Commission of Audit report on how to slash federal spending.

Among the report's key reforms is suggesting patients pay a mandatory $15 fee to see their GP in return for a Medicare rebate.

After 15 visits during a year, the charge would be halved.

The commission claims it will reduce the number of unnecessary and trivial GP visits.