Air New Zealand is reviewing 60 engineering jobs as the airline shifts heavy maintenance work overseas.

The airline has already had Boeing 777s and 767s worked on in Singapore and is now looking for overseas contractors for heavy maintenance on its entire wide body fleet.

While about 60 roles would be assessed during the next six months it was possible some of them could be redeployed to other Air New Zealand operations, the airline said.

The Engineering Printing and Manufacturing Union (EPMU) said it is disappointed the work would go offshore and had fought to keep the jobs here.

"We believe we are a world class facility with world class engineers and a top safety record around engineering. We want that assurance that people flying Air New Zealand have our top safety brand and our tradesman on it," said the union's director of aviation organising Strachan Crang.

"This was announced 18 months ago when the figure of jobs was 137. This is now the last group to go after the volunteers."

Jobs had already been lost by attrition and voluntary redundancies, he said, but more could be done to keep heavy work -- where engines, undercarriages and airframes are stripped down -- in this country.

"Sadly what we've been doing is arguing about the process concerning redundant workers and not enough work has been done to try and get work for them here," Crang said.

One worker said staff were "absolutely gutted" by the moves.

"The only work that will remain in Auckland is A-Checks on jets and line work, all remaining heavy maintenance will be carried out by foreign staff and done in Singapore," the worker said.

Air New Zealand's chief operations officer Bruce Parton said modern aircraft needed much less heavy work and keeping staff here for increasingly fewer checks was not viable. The airline's Dreamliners wouldn't need a scheduled major check for nine years.

"The issue isn't really the cost base, the issue is that there's no work."

At the end of this week staff in affected areas would get notification of whether there would be a future role for them and this would be followed by an opportunity to appeal.

The final outcome of this process would be known by the end of next month.

There were opportunities for affected staff in other areas of the business and later this month the airline would run a jobs expo to showcase various roles including regional maintenance in Nelson, Safe Air and its cargo division.

Parton said Air New Zealand and Virgin Australia were now looking for long-term arrangements for their Boeing 777s.

Suggestions that overseas engineers were not as good as those here were not right.

"Any suggestion that we have the only skilled engineers in the world is just rubbish, we have skilled engineers but to suggest that others don't is just not the case."