Air New Zealand said the impact of the Christchurch and Japan earthquakes significantly hit its long-haul passenger numbers in May.

It has also won its second contract to fit out a luxury jet "for a sub continent client."

The airline said it carried 892,000 or 1 per cent more passengers in May than in the same month a year earlier but demand, or revenue passenger kilometres (RPKs) fell 2.8 per cent, reflecting a 9.3 per cent fall in long-haul passengers.

The Japan route was most affected with passenger numbers down 12 per cent.

The airline said its overall capacity, available seat kilometres (ASKs) fell 3.9 per cent in the month while its load factor rose 0.9 percentage points.

Short-haul passenger numbers were up 2.5 per cent with domestic demand increasing 3.4 per cent.

However, a 4.9 per cent capacity increase meant its domestic load factor fell 1.1 percentage points to 79 per cent.

Tasman/Pacific demand rose 4.4 per cent to 78.9 per cent from May last year.

"Group-wide yields for the financial year to date were up 1.4 per cent on the same period last year with May yields, excluding the impact of foreign exchange, up 3.7 per cent.

That reflected a 2.6 per cent fall in short-haul yields partly due to new seats while long-haul yields were up 4.3 per cent.

The company said 79.2 per cent of its domestic flights departed within 10 minutes of their scheduled departure time.

Air New Zealand said its Altitude Aerospace Interiors won a contract to outfit a new Boeing Business Jet 737 "with a luxurious state of the art interior."

It expects the jet will be ferried to New Zealand early next year and its Altitude team will spend the best part of the year fitting it out "with a luxury bespoke interior to meet the clients' exacting standards."

In March, the airline said it didn't expect to be profitable in the six months ending this month and that normalised net earnings for the year ending June 30 were expected to be below $100 million.

It reported $137 million in normalised earnings for the previous year.

Air New Zealand shares are trading at $1.10, down 1 cent from Friday. They have dropped from a high of $1.54 early this year.