Western Australia's domestic economy grew at 2.1 per cent in the September quarter - well ahead of the national growth rate of 0.2 per cent.
Treasurer Eric Ripper said the State Final Demand figures showed the State's domestic economy growing at 6.3 per cent in annualised terms.
"This was the fastest growth rate of all the mainland States, with Tasmania slightly ahead on seven per cent," Mr Ripper said.
New South Wales grew at 3.1 per cent, Victoria at 3.9 per cent, Queensland at 4.4 per cent, and South Australia at 3.4 per cent.
The Treasurer said the annual average growth rate was higher than the current Budget forecast of 2.25 per cent for 2005-06.
"That is because household consumption has been far more resilient than we anticipated, contributing 2.9 percentage points of the 6.3 per cent growth rate," he said.
The figures show that business investment grew by 17.8 per cent during the September quarter.
"Business investment was driven by new machinery and equipment investment, which was up 33.1 per cent, as well as new engineering construction, which increased 21.6 per cent in the quarter," Mr Ripper said.
The SFD figures followed the release of ABS data showing WA recorded a $26.8billion trade surplus in the 12 months to October, compared with a national deficit of 19.2billion.
Other figures showed a 21.1 per cent increase in building approvals for October.
"Western Australians are building new homes, buying new cars and establishing new businesses because they know that this State's economy is in good hands," Mr Ripper said.