Tararua District mayor Tracey Collis said: "This is absolutely devastating news.
"To lose your job at any time of the year isn't good, but this news coming at this time of the year so close to Christmas just adds to the stress levels for families."
However, Collis said she hoped opportunities could be found for the staff locally.
"The staff at RCR Energy have highly technical skills, but we've some wonderful engineering companies in our district, it's what we are known for," she said.
"The Tararua Business Network is here and will help RCR and the affected staff in whatever way they can."
On Tuesday morning, RCR Energy told the 49 staff at its Dannevirke boiler manufacturing plant that 20 jobs would need to be cut to keep the plant afloat, E tū union organiser Laurel Reid said.
"Workers were reeling after the company announced pending job losses related to its Australian parent company RCR Tomlinson being put into administration," Reid said.
RCR Energy in Dannevirke employs 49 workers, including management and support roles, she said.
"This is a massive blow for the workers and the small community of Dannevirke."
Details of the redundancies are expected to be announced in a week's time, Reid said, "but for 20 people, it won't be good news and it's through no fault of their own".
She said the union and workers understood the cuts were related to the RCR Energy's parent company, RCR Tomlinson, going through liquidation.
RCR Tomlinson was one of two companies awarded a joint-venture contract to build Auckland's City Rail Link, but it was placed in a trading halt on November 12, before being put into administration nine days later.
Wairarapa MP Alastair Scott said it was up to politicians to ensure the economy was robust and moving.
"It's a bugger for those affected. Losing your job any time, especially before Christmas, isn't good," he said. "[But] I'm sure those affected will get jobs."