Australia faces new pressure to open up lucrative air routes across the Pacific, this time from the US.

United Airlines has told the US Government it should use moves by Jetstar and Virgin Blue to establish trans-Pacific services as a lever to negotiate an open-skies policy with Australia.

The giant carrier, the only US airline to fly direct services from the US's west coast, says Australian carriers have found themselves "hoist on the petard constructed by their own protectionist policies".

United says the US should use the leverage created by the situation "to achieve an end of all anti-competitive restrictions for all carriers on all routes".

United notes that it had been prevented from adding the level of service it wanted on US-Australia routes via Japan.

It says: "Rather than offering an incremental exception to the capacity limits to accommodate Jetstar's schedule, the US should offer Australia and its carriers the opportunity to operate services without any restriction on capacity or routings by entering into an open-skies agreement."

United's call adds to existing pressure on Australia from airlines and governments in Singapore and the Arabian Gulf states to liberalise aviation access.

Their requests have foundered on Australian Government policy aimed at making the playing field as level as possible for Australian carriers by seeking what it calls "equitable balance" for rights it gives away.

Qantas argues that many carriers gain advantages from direct government or regulatory support that it does not receive. It includes United in this category because the US carrier was able to restructure under Chapter 11 bankruptcy protection.

The present bilateral air services agreement between Australia and the US places no restriction on how many airlines from either side may fly on South Pacific routes but restricts newly designated carriers to four services a week unless the two sides agree otherwise.

Jetstar, which made its application in June, wants to fly five times a week to Honolulu, and Virgin, which has yet to formally apply, wants daily services.

A spokesman for Transport Minister Warren Truss said the Government would take "a generous and supportive position" if a US carrier was asking for more than four weekly services across the South Pacific.

"We would hope the US Government would say the same thing," he said.