Plans have been put forward for new homes and a public park at the former Llanwern steelworks in Newport.
House builder Persimmon wants permission to build 311 two, three and four-bedroom houses on the site.
A related application from developer St Modwen is to build a £5m access road, which would pave the way for future development of a public park.
There are long-term hopes to develop 4,000 new homes, library, school and other facilities in the area.
If the initial plans get the go-ahead, work is scheduled to start this summer.
Developers have spent four years clearing the site.
The old heavy steel-making plant closed with the loss of 1,300 jobs in July 2001, although there is still a finishing mill at Llanwern.
Nick Alexander, residential land manager for St Modwen, said the development would be known as Glan Llyn.
"Glan Llyn is an exciting regeneration project for Newport and these planning applications mark important milestones for the entire re-development of the site.
He said long-terms plans for the site over the next 20 years would see it transformed into a thriving business and residential community.
The planned £1bn sustainable community will eventually house 4,000 new homes and provide 6,000 new jobs locally, said the developer.
"The public park will be the first to be developed in Newport for several years and will be linked to the first phase of homes via pedestrian bridges crossing a watercourse," said Mr Alexander.
"It will provide a cricket field, games area, play facilities and will offer acres of green space, open woodland, a parkway and two lakes.
"The park will fit in with our vision to establish Glan Llyn as a sustainable community where people can live and work as well as relax."
Glan Llyn is one of four regeneration schemes currently underway by St Modwen in south Wales.
In Neath Port Talbot, the developer is behind a scheme to transform three former BP sites into new employment, residential and education schemes, including the £1.2bn Coed Darcy development in Neath and proposals to develop the new Bay Campus with Swansea University.