Nearly 2000 union members at the Ministry of Justice are voting on whether to take strike action later this month, after fair pay negotiations for female workers stalled.
The proposed strike for court registry officers, victim advisors and others will be a two-hour stoppage on September 19, the Public Service Association (PSA) said.
"Our members at Justice work hard to keep the court system going," PSA national secretary Erin Polaczuk said in a statement.
"Many of them are women, and they do crucial jobs such as court registry officers, court reporters, victim advisors and Family Court co-ordinators.
"They deserve to be properly valued for the work they do in making sure the justice system runs smoothly and fairly."
The average female employee at the ministry is paid 15 per cent less than the average male worker, the PSA said.
It is a larger gender pay gap than the average public sector department of 12 per cent.
The Government requires all public service employers to end the gender pay imbalance by 2020.
"The PSA believes the ministry does not properly value some female-dominated roles - and our efforts to strike a deal to reduce this pay gap and have staff properly valued have so far come to nothing," Polaczuk said.
"These are not highly-paid workers: Last year, Justice had the third-lowest average salary in the public sector, and we believe they are slipping back even further."
Polaczuk said strike action is "always a last resort" but PSA members "feel like they have no other alternative".
"The PSA remains ready and willing to negotiate in order to correct this unfairness," she added.
Ministry of Justice chief executive Andrew Bridgman told the Herald in a statement the ministry remains open and committed to continued negotiations.
"We are willing to meet at any time," he said.
"We have offered a 5 per cent increase over two years, which is consistent with agreements reached by other government agencies. The PSA have asked for more than 13 per cent over the same period."