Prime Minister Tony Abbott has left the door open for a sell-off of less-than-substantial commonwealth assets, as well as Medibank Private.

The government is hoping it can raise $4 billion from the sale of its private health insurer.

That’s the only major asset it plans to sell at this stage, even though Mr Abbott says he can’t guarantee what is in government ownership now will stay that way forever.

“But we don’t have any plans to sell any commonwealth assets of substance, other than Medibank Private,” he told Fairfax Radio on Friday.

Mr Abbott defended the sale of Medibank Private, saying it was perfectly reasonable given the highly-competitive private health insurance sector.

“It doesn’t seem to make much sense to lock-up many billions of dollars in a government-owned insurer,” he said.

Treasurer Joe Hockey has been talking to his state and territory counterparts about how a potential $130 billion of government assets could be sold and proceeds used for new infrastructure ventures.