Air New Zealand expects to create almost 40 new jobs with changes to its aircraft maintenance business.

The airline said it would concentrate on jet maintenance work at its Christchurch base while switching turbo propellor heavy maintenance to Nelson.

The Nelson facility would service Mt Cook Airlines' 11 planes which would create an additional 30 jobs while new contracts would add eight further positions in Christchurch.

The changes would present opportunities for staff facing redundancy at Safe Air in Blenheim, the airline said.

The Engineering Printing and Manufacturing Union welcomed the airline's move.