The investors paid $3.23 million at auction on Saturday for the six-bedroom house on level land at 30 Craik Avenue, which they plan to subdivide.

Selling agent John Pierobon, of Grandland Real Estate, said the buyers would apply for development approval to subdivide the land into about 24 residential lots.

"You'd be talking roughly 350-square-metre block sizes and based on the current market, they would sell for about $400,000," said Mr Pierobon.

From the overall figure of about $9.6 million, the new owners will need to pay between $2.5 to $3 million in subdivision costs, which include council fees, state government levies and services such as sewer and drainage, gas, electricity and road works.

Approval was expected to take about 12 months from the date of submission of plans to council.

Mr Pierobon had a reserve of $3 million and bidders registered. All were investors or developers.

"It's part of the south-west growth area," said Mr Pierobon. "It's about three kilometres from the new Leppington station and [planned] Badgerys Creek airport is 15 kilometres away."

He said the airport was a major driver of prices growth in the area. "There is a very strong investor market in this area. Buyers looking for safe bets. These areas have so much growth ahead of them."

The vendors who have lived on the property for nearly 30 years plan to head towards Camden to re-establish themselves in another semi rural environment.