Up to 100 Safe Air workers face redundancy after Air New Zealand announced this week that it plans to cut around 100 aircraft engineering jobs at the Blenheim site.
The announcement follows the overseas contractor's indefinite postponement of its contract for major upgrade work on the Royal New Zealand Air Force's C130 aircraft.
It is understood the work will now be conducted by a Canadian contractor in the US.
EPMU national secretary Andrew Little says the union will work closely with its members and with Air New Zealand to make sure as few members are displaced as possible.
"These are highly skilled, relatively highly paid jobs and any redundancies will be a huge blow to the Blenheim community and to the local economy.
"The EPMU will be working to save as many jobs as possible and to make sure the process is fair.
"We expect to get more detail over the next couple of weeks and we'll be working with our members to make sure this is done properly," he said.
EPMU organiser George Hollinsworth has been onsite most of this week meeting with members and management.