Swansea Council is working to drive forward £500m (US$760m, €663m) plans for a major mixed-use regeneration project spanning two city centre sites.

The council has unveiled outline proposals for the Civic Centre and St David's sites in the Welsh city and is now asking developers to work on early ideas for the sites and come back with specific plans. It hopes to have preferred developers on board by early 2016.

The authority plans to sell the Civic Centre and relocate its offices to make way for what it describes as “landmark tourist developments” and high quality public spaces. Swansea University is also exploring the potential for a hydro hub research and development facility on the site that could include an aquarium.

A retail and leisure destination is being earmarked for the St David's site that could include shops, restaurants, a public square, a cinema and a new office development. A wide, tree-lined 'sky path' for pedestrians that would cross over Oystermouth Road has been proposed to link the city centre with the waterfront.

"Both sites have now been put out to the international marketplace but the next step is to engage face-to-face with regeneration experts in the private sector and ask them how they can transform our ideas into specific plans,” said Swansea Council leader Rob Stewart.

"Our plans won't be funded by council money. We'll be looking to make them work by seeking alternative funding sources and investment from the private sector. We're determined to deliver and would urge the whole city to get behind us."