Air New Zealand will revamp its economy in its widebody international fleet to give up to 10cm more legroom for passengers who are willing to pay extra.

Economy Stretch seats will have a 35in (88cm) pitch - the distance between seats. This is up from the standard pitch that starts at 31in in economy class.

The airline has not released details of prices for the new seats but in May, when it first revealed preliminary work on the project, said it could be around the same level as other airlines which have similar products. This could mean an extra $150 to $250 for a transpacific flight.

Those in Economy Stretch would also get a premium headset and a special pillow.

The new seats will be available on Boeing 777s and 787-9 Dreamliners from the end of next year.

Chief revenue officer Cam Wallace said today the new economy seats were aimed at bringing more choice. It was a way of targeting price sensitive customers who were willing to pay for extra legroom.

''We know one size doesn't fit all and we want customers to have a fantastic experience whatever the cabin.''

Economy passengers had told the airline that they wanted more space and comfort.

The planes being fitted with Economy Stretch now have between 275 seats and 342 seats in total.

''While our premium cabins will remain the first choice for those wanting all the luxuries, Economy Stretch is a step-up at a competitive price and we're confident it will appeal,'' said Wallace.

The new product is different to premium economy where there are fewer seats in a row and other comforts, including better food.

Air New Zealand Alliance partner United Airlines has had "economy plus" seating for many years and they are popular with passengers. They are part of the main economy section and the seats have an extra 12cm between them. For a transpacific flight, United charges around US$170 ($269) extra.

Like other airlines Air New Zealand is fitting fewer basic economy seats throughout the fleet as leisure travellers - the airline's prime market - are prepared to pay more for more comfort.

More than half the area of its Boeing 777-300s had premium or premium economy seats at the moment.

The new economy seats are part of an overhaul throughout the entire cabin with details of a major revamp of business class seats set to be released soon.