China fears US bomber visits to Aust

China has expressed concerns about reports US supersonic long-range B-1B bombers could soon conduct training exercises from an RAAF base in Australia's north.

"Any bilateral cooperation must not jeopardise a third party's interests," Foreign Ministry spokesman Hong Lei told a press briefing.

Neither Prime Minister Malcolm Turnbull nor Foreign Minister Julie Bishop has denied the reports.

The commander of US Pacific Air Forces, General Lori Robinson was quoted in media reports saying B-1B bombers and tanker aircraft would regularly rotate through northern Australia rather than exercise in Australia on an ad hoc basis. B-1B Lancer bombers, which can carry nuclear weapons, have visited Australia previously, including to participate in air shows.

Mr Hong dismissed US-commissioned polling that shows a majority of Australians have concerns about the 99-year lease of Darwin port to a Chinese firm Landbridge.

"It is not necessary for the Australian public to be so suspicious about that," Mr Hong said.

US Ambassador to Australia John Berry played down the opinion polling, saying it was common practice for the US State Department world-wide.

"Australia alone determines its sovereign criteria for investment projects," he said in a statement.

"Such low level polls do not reflect US government views, policy, or position."

The US had discussed the port issue with the Australian government and had concerns addressed, Mr Berry said.