Businesses have urged the state government to fast-track the second stage of the multibillion-dollar Parramatta light rail line to Sydney Olympic Park, fearing it will be delayed.

The pleadings come as Transport Minister Andrew Constance says businesses and residents along the route of the first stage of the new line through Parramatta will be spared major disruptions which have plagued construction of a $2.1 billion light rail line in central Sydney.

Major work on the first stage from Westmead to Carlingford via Parramatta's CBD – which will cost $2.4 billion − will start next year, after the government awarded two major contracts.

Construction will start next year on the first stage of Parramatta's light rail line.

It prompted businesses to urge the government to release the business case and concrete timelines for the building of the second stage of the light rail line linking Parramatta to Olympic Park via Rydalmere, Melrose Park and Wentworth Point.