A construction workers union on Wednesday said there has been a sharp drop in private sector building projects and the government should take up the slack.

The Hong Kong Construction Industry Employees General Union said local construction workers fear for their jobs, and salary freezes are widespread.

The union said it recently polled over 2,000 members and 35 percent of respondents reported being underemployed. Over 70 percent rated employment prospects this year as being worse than last year.

The union's chairman, Chau Sze-kit, said the industry is facing challenges.

"The number of private sector construction projects has fallen. Although the number of government projects remains unchanged, the amount of construction expenditure in both markets is half-half. Last year project volumes were already down, but this year they have decreased by two-thirds," Chau said.

"We have architects and engineers who have seen cuts to their salaries or who have been made redundant, meaning even those higher up in the construction industry are being affected. If they have nothing to do, the prospect for construction workers will also not be good in the coming one to two years."

More than 80 percent of workers surveyed said the government's labour importation scheme has led to unemployment and a reduction in salaries.

The union urged the government to roll out public work projects, expedite the implementation of redevelopment and maintenance projects to boost job openings in the short term, and make timely adjustments to the labour importation scheme to protect local workers.

The union also said it has received dozens of requests for assistance regarding monetary disputes, involving hundreds of workers. The complaints mainly involve holiday rights and unpaid wages, the union said.

It added that since July this year, it has handled around 20 cases of unpaid wages caused by a major contractor owing payments to a subcontractor.

The union urged the Legislative Council to quickly pass the Construction Industry Security of Payment Bill to protect workers, saying a dispute can take around 1.5 years to be settled at the Labour Tribunal.