Pay rates for Ministry of Justice court security officers are part of the reason why court staff across the country will strike on Wednesday.

Court staff are the latest public sector workers to take up placards and go on strike.

Their union says the Ministry of Justice's latest pay offer does nothing to close the large gender pay gap, while the ministry says the union is asking for well above what other government agencies are getting.

Court workers are going to follow the same path as nurses, teachers and learning support workers by going on strike on Wednesday.

Ministry chief executive Andrew Bridgman said officials offered a 5 per cent pay increase over two years, similar to what other government agencies had agreed to, but the Public Service Association's demands amounted to 13 per cent over the same period.

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Negotiations had gone on for several months and the ministry was willing to return to the table anytime, he said.

Public Services Association organiser Brendon Lane said the ministry's offer was 3 per cent one year, then 2 per cent the next, while the union wanted 3 per cent in each of those year, he said.

But the main issue was changes to pay bands, which would put certain roles, including victims' advisers and court reporters, who record what is said during hearings, on a lower pegging to other jobs.

Those roles were almost completely filled by women and would only extend the gender pay gap in the ministry, which was already larger than other government agencies, Lane said.

"What people don't appreciate is they are in courts day after day, listening to all the horrible things people do to each other."

However, their pay bands would have them being paid similar rates to secretaries – something Lane described as "degrading".

The ministry also had poor staff retention in those roles, with many only staying for two or three years, he said.

"People realise it just isn't worth the money and they leave."

Court security staff, who are set to get new powers that increases their authority to seize items and detain people, were only being paid just above what security guards would get, Lane said.

"For the ministry to say: 'We are prepared to throw you this bone here, for all the danger you face', we think it's unacceptable."

The strike would only be for two hours, from 10.30am, to avoid too much disruption, although some courts may have to close for that time, Lane said.

Staff were also doing other forms of industrial action, such as work-to-rule and not doing overtime.

"We are hoping the ministry and ultimately the Government puts more on the table."