Big business is warning that a trillion-dollar capital investment pipeline is being threatened by the high-cost nature of the Australian economy.

The Business Council of Australia says Australia's reputation for low productivity and outdated work practices means only half of a potential $921 billion of investments has been locked in.

While the BCA has welcomed the surprisingly strong economic growth in the March quarter, president Tony Shepherd said Australia should not be complacent about the mining boom always coming to the economic rescue.

"The biggest risk to the Australian economy at the moment is that it's largely dependent on growth in the resources sector, and we know that most of the rest of the economy is struggling," Mr Shepherd said.

"So the efficiency and the continuing growth of the resources sector is of course vital for the whole community in terms of wealth creation and jobs creation."

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The council has delivered the warning in its study "Pipeline or Pipedream?", which was released before an economic forum hosted by Prime Minister Julia Gillard next week.

Some of the report's key finding include concerns that:

Australian resources projects are 40 per cent more expensive than those on the Gulf Coast of the United States.

Australian resources projects are 40 per cent more expensive than those on the Gulf Coast of the United States. Australian labour is 35 per cent less productive than in the US Gulf Coast for projects near cities, and 60 per cent less productive for projects in remote locations.

Australian labour is 35 per cent less productive than in the US Gulf Coast for projects near cities, and 60 per cent less productive for projects in remote locations. Infrastructure is more expensive to deliver in Australia than the US, with airports 90 per cent more expensive, hospitals 62 per cent, shopping centres 43 per cent and schools 26 per cent more expensive.

Mr Shepherd's comments back concerns from BHP Billiton chief executive, Marius Kloppers, who yesterday pointed to Australia as a high cost, high risk economy.

"We are in a global competition for capital and in things like iron ore or in coal, we've got growing competition from other countries in the world. And if we become more expensive, or too expensive, then those projects may not occur or may go elsewhere," Mr Shepherd said.

Mr Shepherd said it was possible that BHP would contemplate exiting some projects because of low productivity and high risk.

"They haven't committed yet, for example, to the Olympic Dam project in South Australia, and they're making a decision on that in the future, so that is one project which is under consideration," Mr Shepherd said.

"They are a sensible company, well-managed. They have got a lot of capital but they haven't unlimited capital, and they will go where they think they will make the biggest return."