As the US government grapples on addressing its budget issues, Australia's planned upgrade on its air defence capability could run into more glitches, according to the country's defence chief.

Already hampered by delays and rising costs, Australia's proposed purchase of F-35 combat planes from the United States could meet new issues as the US Congress and US President Barack Obama struggle to strike a compromise that would resolve America's debt crisis, according to Defence Minister Stephen Smith.

With the two branches of the US government currently deadlocked on any possible resolution to the crisis, economists have warned of a likely default by the US Treasury the subsequent credit rating downgrade for the world's biggest economy.

The ensuing spending cuts, Smith said, could mean that delivery of fighter jets to Australia would be further delayed but he pointed out that this early the country is mulling on possible alternatives, including the acquisition of Super Hornets that would continue the program commenced then by the Howard administration.

In a report by The Australian, the country spent some $6 billion to 24 units of Super Hornets to its air force fleet and sustaining that program, according to Smith, is an attractive option for the defence ministry.

The defence chief, however, noted that the Australian government needs to closely rethink its defence upgrade strategies as ABC quoted him on Wednesday as saying that "we need to take this step by step ... and I don't want people to run or leap to a conclusion that is the path we will go down."

Australia has been mapping a defence blueprint that aims to realise an operational squadron of F-35s by 2018, which will be part of up to 100 units set to be acquired by the country from the US Air Force.

However, budget problems appear to be preventing America from meeting the calendar set by Australia, with Smith already giving notice to the planes' supplier that Canberra is considering dropping the deal altogether, arguing that delays and cost blowouts are hurting the country's defence program.

Experts have suggested that jettisoning the JSF deal could actually benefit Australia as Hugh White of the Australian National University's Strategic and Defence Studies Centre was quoted by The Australian as saying that "the longer it is delayed and the more the price is increased the further the cost-benefit analysis drifts away from that aircraft."

White added that "Smith is right to start asking questions about whether we might be better to move away from the JSF and buy more Super Hornets," which he noted was actually a brilliant move on the part of the Howard government.