It's down to three contenders for the contract to build Ottawa's $2.1 billion light-rail project.

Ottawa Mayor Jim Watson announced the three groups on Friday, which includes some of the biggest names in business.

"Collectively, these firms have built over $100 billion in light rail projects and 2,000 kilometres of tunnels in cities across the globe," said Ottawa Mayor Jim Watson.

"These companies have built successful projects in cities such as Athens, London, Madrid, Reims, Sydney, Calgary and Vancouver. These are some of the biggest, most experienced, and most capable firms in the world."

The groups are the Ottawa Transit Partners, which includes Bombardier, the Rideau Transit Group that includes Ellis Don and SNC Lavalin, and the Rideau Transit Partners led by Bouygues Travaux Publics.

The list includes VINCI Concessions, which worked on the Confederation Bridge between New Brunswick and P.E.I. and, Bouygues Travaux that worked on the Chunnel between France and England, and Colas Rail.

Not on the list yet is Siemans, who were awarded the contract for Ottawa's cancelled north-south rail project. The company could still be invited in the future.

The groups will compete for the contract from now until July 2012, with local companies getting a chance to showcase their firms in a job fair.

"Infrastructure Ontario advises us that from their experience, 80 per cent of the labour for this project will come locally from Ottawa," said John Jenson from the City of Ottawa.

A winner to be chosen in December 2012 with construction scheduled to start early in 2013.

With a report from CTV Ottawa's Graham Richardson