A project to create 12,000 homes in Adelaide's northern outskirts will drive unnecessary urban sprawl, according to the SA Greens — but the billionaire developer behind it says it will help improve housing affordability at a time of record prices.

After more than a decade of planning, work is now going ahead on the Walker Corporation's Buckland Park project near the towns of Virginia and Angle Vale and their surrounding market gardening communities.

The corporation said the $3 billion project, called Riverlea, would create the state's "largest master-planned community" and assist with "post-COVID economic recovery".

But the project has attracted criticism since its inception, because of its proximity to the flood-prone Gawler River and concerns over urban sprawl.

Developer and executive chairman Lang Walker said the intention was to create a community that would drive economic growth outside of Adelaide's CBD.

"Not everyone's going to be working in the CBD. We've got another very large industrial estate out there in the vicinity," he told ABC Radio Adelaide.

"This will generate self-employment in that whole region itself. It's a community within a community.

"This project has a life of 20 years, maybe 25 years, and that brings shopping, it brings 10,000 jobs over the period of the house-building and all the trades."

Adelaide property prices have hit record highs in recent weeks, and Mr Walker said house and land packages would be available for less than the price of "a block of land in Sydney and Melbourne".

"We're pitching into the affordable market and bringing in all the community benefits there," he said.

"It's a great opportunity to get people into houses."

But Greens MP Mark Parnell has previously labelled the project a "ghetto in waiting" and said planning experts had consistently flagged problems with it.

"They knew it was a rotten project 14 years ago, and it's still a rotten project," he said.

"This is a bit like a zombie movie. I thought it was dead and [then] you look and it's come back to life.

"There's a whole range of issues ... it's a flood-prone area."

Local teacher Robyn Lewis said some produce growers were worried about the impact on an area she said was "called the 'salad bowl' for a reason".

But she said the area was "blossoming" and that the project would deliver much-needed amenities.

"We don't have a lot of public transport out here and I'm sure, in the infrastructure [plan], that will be looked at," she said.

"Schools are going to be built in the area [which] is fantastic for parents — they don't have to load their children onto a bus in the morning, with all the worries that come with that.

"The fact that there's going to be shopping centres will be great."

Existing roads to be upgraded

Mr Walker said the project would include more than 450 hectares of open space and 50 hectares of lakes and waterways.

"There's close on 40 kilometres of bike paths," he said.

"We're investing $3 billion in it so we're very confident that this is what Adelaide needs."

But Mr Parnell likened it to the infamous Mount Barker development, which then-planning minister John Rau in 2011 conceded had been poorly handled.

"Mount Barker has now become a case study in appalling planning," Mr Parnell said.

"As a city, Adelaide — the idea that we've come to is that they're should probably be some limit to urban expansion on the fringe.

"Unless we want urban sprawl forever, unless we want Los Angeles and to be like that, we do need to have a containment boundary."

A spokesperson said the Department for Infrastructure and Transport would "continue to monitor population growth" and "assess public transport requirements" in the area.

"Roadworks are being undertaken to construct a signalised intersection at the junction of Port Wakefield Road and Angle Vale Road as part of the residential community development Riverlea," the spokesperson said.

"Traffic lights at the junction of Port Wakefield Road and Angle Vale Road are expected to be installed in mid-2021.

"The works will include some road and speed restrictions to facilitate construction."

Ms Lewis welcomed the installation of the traffic lights at the intersection.

"There have been a few accidents on that corner and with more traffic there's a possibility of more," she said.