Kevin Rudd may privately badmouth China, but his economic strategy is heavily dependent on continued strong Chinese growth. His earlier return to surplus depends on the new mining tax delivering massive new tax revenues. His new tax also obliges the Commonwealth to reimburse 40 per cent of unrecovered losses if a project fails. So were Chinese growth to slow, not only would mining tax revenues decline but, in a double whammy to the budget bottom line, if projects were to fail the Commonwealth would be called on to pick up its share of losses.

So how sound is the government's assumption that the China boom will continue for many years?

China's extraordinary growth and development is awe inspiring. But it is capable of making the same mistakes of excessive spending and borrowing as any other country.

As the historian Niall Ferguson recently observed, blow-outs in public debt are always and everywhere ''consequences of political weakness …Excessive expenditure and insufficient taxation, failures to make decisions about unsustainable fiscal policies are political, they are not the results of profound economic weakness."

Working out the true level of government debt in China is very difficult. Nobody believes the official figures of about 20 per cent of GDP. But how much higher is it?