The Meat Workers Union and the freezing works company AFFCO are in a stand-off as the Employment Relations Authority prepares to step in.
Strike action has been taking place since the end of February this year as the parties battle over a collective contract.
On Wednesday, AFFCO lifted lock-out notices on about 300 workers, who then voted to strike in solidarity with 450 colleagues still locked out.
The union says it won't lift its strike action until the company completely withdraws its lock-out notice, which the company says it won't do until the union stops the strike.
AFFCO operations manager Rowan Ogg says the company had offered to let all workers return over a couple of weeks, but wanted the strike notice lifted as a good will gesture. He says the union refused.
Union spokesman Dave Eastlake says union negotiators suggested a gradual lifting of the lock-out over two weeks, but were rebuffed by AFFCO.
He says union members won't go back to work until they're assured that everyone will be allowed back.
Mr Eastlake says he hopes the Employment Relations Authority can set a date for the facilitation hearing on Thursday. More mediation is set down for Monday and Tuesday.
Demand for food parcels
More than 100 unionised meatworkers at AFFCO's sheep and beef plant in Wairoa have been locked out for nine weeks.
The company is the biggest employer in the town and volunteers at a resource centre in Wairoa say there is a growing demand from locked out workers for essential household items and non perishable food.
Terese Turipa who administers the centre, says every week about 250 families from all over Northern Hawke's Bay and some from Gisborne collect food parcels.
Ms Turipa says volunteers are also doing their best to keep locked-out workers and their families positive.
Mayor Les Probert says the industrial dispute is having a negative effect on the town and retailers he's spoken to are suffering.
But he says it is not as bad as two years ago when a dispute between AFFCO management and the Meat Workers Union over a proposed new site agreement went on for about four months.
Rowan Ogg of AFFCO says the dispute is hurting the company but the priority is to obtain a modern, clear and flexible agreement that will take the firm into the future, and the company is not about to compromise that.