The Public Service Association says industrial action will continue if the Ministry of Justice does not change its position on stalled wage talks for court staff.
About 1000 Ministry staff who collect fines and work at courts and tribunals walked off the job on Monday over a pay dispute.
The PSA says the action shut down court sittings throughout the country and was an escalation of previous industrial action.
National Secretary Richard Wagstaff says they're keen to return to the bargaining table, but not if the ministry refuses to change its position.
"If they wish to signal that they are prepared to negotiate and they are prepared to find solutions to those problems, I believe we can get back to the table."
As well as nationwide strikes, some court staff are staging local strikes where staff at individual courts are walking off the job for varying lengths of time.
Mr Wagstaff says on average, justice workers are paid 6.3% below the pay median for the public service.
Lawyers support pay claims
A Lower Hutt lawyer says there is a lot of sympathy within the profession for striking court staff.
Chris Nicholls, a criminal and family lawyer, says the industrial action has been disruptive but there has been little complaing from either lawyers or judges.
"I consider the reason for that is that many of the lawyers whom I've spoken to support the staff, realise that they work in difficult situations, with difficult people.
"Compared with other public service employees they're quite considerably underpaid."
The Ministry of Justice maintains it cannot afford the PSA's claim, which it believes will cost about $113 million over three years, but says it is committed to resolving the dispute.
The ministry says it is working hard to minimise the disruption to court users and has apologised for any inconvenience.