Sydney's troubled light rail line is set to be opened in stages with the first trams expected to begin carrying passengers from Randwick to Circular Quay in December, followed by the branch line to Kingsford several months later.

Construction of the Randwick branch of the line is the most advanced part of the multibillion-dollar project, and trams have been running from Moore Park to the end at a High Street terminus for several weeks as part of testing.

However, construction of the other branch of the line along Anzac Parade to Kingsford has been dogged by problems and is further behind.

Light rail vehicles at a stabling yard next to Randwick Racecourse have been undergoing testing. Credit:Louise Kennerley

Transport for NSW confirmed that it was in discussions with the consortium overseeing the project about opening the line from Circular Quay to Randwick in December.