The Australian Bureau of Statistics reported the surplus was the second biggest monthly trade surplus on record since June 1997, when the trade surplus was $1.54 billion.
The sum of the seasonally adjusted balances for the three months to September 2008 was a surplus of $2.15 billion, a turnaround of $3.2 billion on the deficit of $1.09 billion for the three months to June 2008.
The value of exports rose by 8% to $26.5 billion and imports jumped 7% to $25 billion, offsetting a slump in consumer and business spending that threatens to tip Australia's economy into a recession.
The main components contributing to the export rise in the seasonally adjusted estimates were metal ores and minerals, up $941 million; coal, coke and briquettes, up $626 million; and other manufactures, up $60 million.
The report showed shipments of metal ores including iron surged 19% and coal gained 14%.
In seasonally adjusted terms, exports of non-rural goods rose $1.6 billion, or 10%, to $17.9 billion.
Partly offsetting these increases was the machinery component, with exports down $42 million.
In seasonally adjusted terms, imports of intermediate and other merchandise goods rose $1.13 billion, or 13%, to $9.58 billion with fuels and lubricants the main components contributing to the rise, up $547million.
However, the ABS report speculates a general weakening of imports and exports in tandem with the domestic economy will test the trade balance in the first half of 2009.