Union members in Darwin have held a protest against working conditions at the Ichthys LNG construction project.

Around 500 workers took to the streets to highlight issues of suicide among FIFO workers, the mental health effects of 4:1 rosters, as well as worksite health and safety concerns.

“Walkways are atrocious and often flooded, there's little traffic management, and sometimes you're working alone with no-one else in your area, there's no buddy system,” one worker told the ABC.

Electrical Trades Union (ETU) assistant secretary for NT and Queensland branch Peter Ong said the union tried to bring up the mental and physical safety concerns with contractor JKC, but made no progress.

“We've been trying to push for shorter rosters on the project, there's been a new industry standard set in Western Australia which is 20 days on 10 days off,” Ong told reporters, referring to a roster change in 2015 for Barrow Island’s Gorgon LNG project.

“This roster is still 28 days on and seven off ... and it's just damaging families.”

The union also claims there have been some discriminatory hiring practices in place that work against local workers seeking time off on weekends.

“The promise was made from INPEX when they came to Darwin that they would provide plenty of work for the local workforce and local Darwin people,” he said.

“They've provided some jobs, but we're seeing more and more locals being knocked back because they want to have days off on the weekend to spend with their families... but they don't want that on the project, they want people to be working seven days a week for four weeks straight.”

A statement from JKC and INPEX says they are committed to their employees’ health and safety.

“We operate under the company's core value of 'Anzen dai ichi' — safety number one,” the statement said.

“It is the way we think, act and promote safety that forms the core of a strong health and safety culture.

“We work to the requirements set out by the Work Health and Safety Act and all incidents at our Australian sites are reported according to the Work Health and Safety Act.”

The companies said the 4/1 roster gave FIFO employees 11 days off out of the 35 in the five week roster.

“In addition, during their 28 days on site, workers accrue time towards two rostered days off,” they said.

“At the end of the 28 days, the two accumulated days are paid out during the employees' seven-day rest and recreation period, or alternatively they can be paid out upon termination of employment.

“Both of these options were agreed with all four construction unions.”