Australia’s economy is growing at a slower-than-normal pace, but is expected to pick up over the next six to nine months.

The Westpac-Melbourne Institute Leading Index, released on Wednesday and which indicates the likely pace of economic activity three to nine months into the future, rose to 3.0 per cent in August, just above its long-term trend of 2.7 per cent.

But the annualised growth rate of the Coincident Index, which gives a pulse of current activity, was 2.7 per cent, below its long-term trend of 3.0 per cent.

Westpac chief economist Bill Evans said it was the first time in 12 months the leading index had been above the long-term trend.

Mr Evans said the bank’s own forecasts were slightly less optimistic than the index, pointing to an annualised rate of gross domestic product (GDP) growth of 2.5 per cent in the second half of 2012, followed by 3.25 per cent growth in 2013.

He said the mining investment boom was likely to remain a major driver of the economy in 2013, despite recent falls in commodity prices.

“Next year, the economy will still be benefiting from a surge in mining investment, although our expectation is that the spending peak will be around year end or early in 2014.”

Mr Evans said the growth rate of the leading index had increased from 0.8 per cent in March.

The major contributors to the improvement were manufacturing (up 1.3 percentage points), overtime worked (up 1.1 percentage points) and productivity (up 1.1 percentage points).