South Australian homeowners in new developments may be charged a separate levy to pay for key infrastructure like roads and sewerage as part of proposed urban planning reforms.

But Planning Minister John Rau says the reforms, to be introduced to parliament, will actually reduce the entry price of home ownership.

Mr Rau said under the new laws developers and land holders will have to contribute regularly over time to the infrastructure costs for new projects, rather than paying for it up front.

“The money is collected by local government and held in a fund specifically for the cost of infrastructure,” he told ABC radio.

He said this will remove a hurdle for investors and provide flexibility in the way essential infrastructure can be provided.

“This will make the entry cost to home ownership lower in many cases,” he said.

The new bill will also define protected environmental and food zones where only parliament can approve housing development, and set a growth boundary around Adelaide to limit urban sprawl.

“This will help to safeguard our important environmental and food production areas from opportunistic and ill-considered residential encroachment,” Mr Rau said.