The barrier effectively ends any hope Singapore Airlines and Emirates had of flying the coveted and lucrative route.

Qantas operates 47 flights a week to Los Angeles.

"The Australian Government has made it clear that it has no immediate plans for additional third-party access to the route at this time," the green paper said.

The continuing ban is among a range of policy proposals that greatly benefit the Australian carrier.

They include changing the Qantas Sale Act to allow easier access to foreign capital, which would boost Qantas at a time when 30 carriers worldwide have been bankrupted by the financial crisis.

"This is a step in the right direction which will set us on an equal footing with other Australian international carriers," new Qantas chief Alan Joyce said.

The green paper, released by Transport Minister Anthony Albanese, will be used to gauge industry response ahead of formal Cabinet approval of a final document - or white paper - next year.

The suggestions outlined yesterday include changing the rules on the size of the stake foreign airlines can take in Qantas and to make private airport owners accountable to state authorities when planning airport-based shopping centres.

The document said the Government wanted to shut out foreign competition on the Pacific to give V Australia, the yet-to-fly offshoot of Virgin Blue, an opportunity to properly establish its trans-Pacific discount operation next year.

Under the existing bilateral arrangement between the Australian and US governments, only Qantas, V Australia, Air New Zealand and US-based United Airlines can operate the route.

The green paper conceded that third-party competition might be allowed in future, but only if in the national interest.

"The maximum national benefit would be sought if a decision is made to trade such access in the future," the paper said.

Singapore Airlines has run an eight-year campaign for the right to operate flights to the US from Australia.

Emirates revealed recently it had been "quietly" seeking Australian Government approval to fly the route.

The biggest change the 205-page green paper proposed involves dispensing with the caps on foreign airline investment in Qantas.

At present no foreign airline can own more than 25 per cent of Qantas and groups of foreign airlines are restricted to 35 per cent, with total foreign ownership restricted to 49 per cent.

Changing the rule would make it easier for Qantas to merge with another carrier.

The flying kangaroo also would be able to formalise the partnership it has with British Airways under which the pair share profits on the "kangaroo' route" to London.

The proposed changes would not affect the Qantas brand or lead to it disappearing from Australia.

The Qantas Sale Act stipulates that Qantas must be 51 per cent Australian-owned, keep its headquarters in Australia, and have an Australian citizen as chairman.

Other changes the green paper proposed could benefit Singapore-owned but Melbourne-based Tiger Airways Australia.

The paper suggested a simplification of the rule on how airline "nationality" is determined when routes are awarded to Australian-based carriers.

Instead of identity being determined by the place of residence of controlling shareholders, the proposal is the determining factor be principal place of business.

Such a change would pave the way for Tiger Australia to compete with Qantas and Jetstar on routes to Asia.