Sydney’s troubled light rail project is at least a year behind schedule, NSW Transport Minister Andrew Constance has been told by the consortium building the project.

The light rail, running from the CBD to the eastern suburbs, was meant to be finished in 2019.

But it’s understood Mr Constance was advised by contractor ALTRAC on Thursday the new completion date was March 2020.

The news comes less than a week after the state government was taken to court by Spanish subcontractor Acciona, which is building the $2.1 billion project.

Acciona has accused Transport for NSW in the NSW Supreme Court of engaging in “misleading or deceptive conduct” in relation to the contract.

The company wants another $1.1 billion from the government, which is fighting the claim.

The light rail was originally budgeted to cost $1.6 billion before a $500 million blowout.

Acciona’s new demands threaten to double the original cost.

Mr Constance on Thursday accused Acciona of playing games and said the government still wanted the light rail finished next year.

Andrew Constance and Gladys Berejiklian are seen reopening a section of George Street in December last year. Photo: AAP

“We want to see it delivered in 2019 as per the project deed,” the minister told 2GB radio.

“It is vital that ALTRAC accelerate and get on with their program. We have businesses and residents being hurt by their actions and inactions.”

Opposition Leader Luke Foley said businesses along George Street were suffering the most.

“The people I’m concerned about are the small business people who are hitting the fence – their revenue is down 60 or 70 per cent or more,” Mr Foley told reporters.

One publican on George Street said small businesses along the once-busy strip were struggling to deal with the lack of foot traffic during construction.

“They are crushing us. We’re an established business and can weather the storm but the mum and dad businesses, the small restaurants, they’re being swallowed up by this,” the man, who wished to remain anonymous, told AAP.

The Labor leader said the government – in particular, Mr Constance and Premier Gladys Berejiklian – was treating business owners as “collateral damage”.

Mr Foley said Mr Constance had handled the project badly but it was his predecessor as transport minister, Ms Berejiklian, who needed to accept overall responsibility.

“I feel a bit sorry for Andrew Constance, I mean, he’s got the hospital pass of this dud light rail project from the Premier,” Mr Foley said.

“She has to explain what her plan is when it comes to light rail because it’s her baby, this project, and it’s a disastrous project.”

ALTRAC on Thursday said work on the project was taking longer than expected due to design changes and the discovery of “unknown utilities”.

The consortium has found more than 1600 unknown services but has still completed about 80 per cent of the utilities work, a spokeswoman said in a statement.

Some 16 kilometres of track has been laid by Acciona to date amounting to 66 per cent of the route, ALTRAC said.

-AAP