More than 100 workers at Affco's Wairoa meatworks have been laid off, just weeks after returning to work.

Work restarted at the plant three weeks ago after the about 200 workers on the lamb and mutton operation had been off work for five months due to an employment dispute between Affco and the New Zealand Meatworkers Union.

Affco operations manager Rowan Ogg said this week's layoffs were due to livestock availability.

"We don't know how long the workers will be laid off for. They were working for a relatively short period of time, about three weeks," he said.

"There were two chains operating and now they're down to one."

A slow season with lambs meant less stock were coming forward, Federated Farmers Wairoa branch chairman John Ross said.

"It's proving to be a later season than we've had in the past. Lambs aren't finishing as quick as farmers would like, so everything has been delayed," he said.

Farmers in the area were drafting only half what they normally would at this time of year as lambs were not ready due to a difficult winter.

"It's mainly to do with the wet period over lambing. Hopefully this recent warm weather could help lambs. They need the good weather and sunshine to help them grow," Mr Ross said.

The layoffs have caused some workers to consider leaving the district, Wairoa Meat Workers Union Resource Centre manager Gail Piper said.

"We were hoping this would be a normal season like last year and we would be working until May or June - for some until August next year, she said.

But many workers were now talking about a plan B, which was getting work away from Wairoa.

The resource centre, which provided food parcels, support and information, opened last month in a bid to help alleviate hardships for union-member families.

The centre provided food parcels, support and information.

There was relief when the call was made to return to work but the union said it would now keep the centre open "for as long as it took".