The small government agency, which has about 100 employees, had offered pay rises totalling 4.5 per cent over three years: 0.5 per cent immediately, followed by raises of 1.5 per cent and 2.5 per cent in subsequent years.

About 55 per cent of the staff who voted opted to accept the deal.

The bureau's head of corporate services, Colin McNamara, said few conditions changed other than a cut to personal leave from 25 to 18 days a year.

"

"I believe the result (55 per cent in favour) reflects a general acceptance this is the best offer the agency can provide when taking into account our constrained financial position, the broader economic climate and what is transpiring across the public service."

Last week, the Treasury became the first department to approve an enterprise agreement under the Abbott government, which has imposed tough rules on bargaining to restrain public servants' salaries.

Staff at smaller agencies such as Comsuper and the Australian Public Service Commission have also endorsed new deals over the past month.

However, Attorney-General's Department employees opposed strongly a proposed agreement this week, which also included a 1.5 per cent annual raise. About seven in 10 of the department's staff voted "no".

remain locked in negotiations, even though their wage deals expired a year ago. Many have not yet had the chance to vote on an agreement.

Under the government's bargaining policy, employers must fund any proposed pay rises through administrative savings or by "cashing out" staff benefits.

Employment Minister Eric Abetz welcomed the ballot outcome at the Australian Transport Satefy Bureau, and used the result to criticise the Community and Public Sector Union's campaign of industrial action.

"Public servants are losing out on wage rises while the CPSU is pursuing its political agenda against the government," he said.

The Australian Transport Safety Bureau investigates aviation, rail and maritime accidents and safety problems.