The S&P/ASX 200 index got off to a good start, hitting 4591.9 points in morning trade.

However, trading softened in the afternoon, with the index reaching an intraday low of 4577.7 points just before midday.

Investors had little local data to take their leads from, instead drawing from a mixed performance on offshore bourses overnight.

At the end of trade, the index fell 0.02% to 4582.8 points, while the All Ordinaries gained 0.02% to 4592.9 points.

Among the sectors, defensive stocks fell into the red, with telecommunications down 0.4% while health care fell 0.5%.

Technology posted a 1.2% dip, however utilities performed well after gaining 0.8%.

Basic materials and industrials were up 0.3% and 0.2% respectively.

Following a string of gains, miners were instead a mixed bag today.

Both the heavyweights were up, with BHP Billiton gaining 0.7% to $A36 and Rio Tinto advancing 0.9% to $62.75.

After gaining 1.7% yesterday, shares in Fortescue Metals Group did the opposite today despite announcing a 2 billion tonne resource upgrade at its Iron Bridge property.

Fortescue lost 0.7% to close at $4.25.

A few other iron ore miners lost ground, with Aquila Resources falling 4.4% to $2.63 while Gindalbie Metals sank 2.1% to 23.5c.

Meanwhile, mineral sands producer Iluka Resources dropped 5.6% to $8.16 after investors reacted negatively to a market update.

Elsewhere, Resolute Mining gained 2.1% to $1.70 and Integra Mining picked up 3.9% to 53.5c.

On the junior end, Castle Minerals fell 18.3% to 9.8c on no news, while Rubianna Resources picked up 6% to 5.3c after providing an exploration update at its Killara project.

The Australian dollar was trading slightly lower at $US1.055.