Volgren, which was bought earlier this year by Brazilian company Marcopolo S.A., declined to comment yesterday but the main union on the site said it had held talks with management about shutting the site by September.

Australian Manufacturing Workers Union organiser Todd Nickle said 43 blue-collar workers would lose their jobs, with staff taking the potential total of job losses to about 60.

‘‘This is a state-of-the-art business, it’s the biggest spray-painting bay in the country, so to be shutting down after just two years, there’s more to this than we know yet,’’ Mr Nickle said.

Deputy opposition leader Linda Burney blamed the state government for the closure, saying that if it had ‘‘kept its commitment to build new buses across NSW this wouldn’t be happening’’.

Transport Minister Gladys Berejiklian said the government’s reform to bus-buying tenders was giving taxpayers ‘‘value for money’’.

‘‘Regrettably, the previous Labor government made an unsustainable promise by deliberately bringing forward bus orders in a cynical election stunt, effectively creating a market bubble for the local bus manufacturing industry,’’ Ms Berejiklian said.

NSW Bus and Coach Association executive director Darryl Mellish said Coalition changes to bus procurement had led to a ‘‘pause’’ in bus buying by existing operators, who did not want to buy new buses while they faced the chance of losing their business in the latest round of route tenders, which were open to all comers.

He was confident orders would resume once the tenders were completed, although official figures showed a steady decline in NSW bus registrations from 703 in 2009 to 130 in the first five months of this year.

The Volgren factory at Kilcoy Drive, Tomago, was officially opened in March 2010 at a cost of $18million.

Its initial contract was to build 150 articulated or ‘‘bendy’’ buses for State Transit’s Sydney service at a cost of $106million.