Air New Zealand has diverted more than 890 tonnes of in-flight waste from landfill two years on from the launch of Project Green.

The initiative, which started in late 2017, sees unused items from a flight service be put onto a subsequent flight.

To be reused, these items must come off the aircraft sealed and untouched.

Cans of soft drink, packets of cookies, boxed tea, coffee and sugar sachets and sealed napkins are just some of items included in the project.

Prior to the establishment of this process, unopened items of these product types taken on board would have had to be incinerated.

Air New Zealand supply chain general manager Chain Chloe Surridge says data captured from the roll out of Project Green in Auckland, Wellington, Christchurch, Queenstown and Los Angeles International airport helps the business to better assess flight loading requirements and to look for opportunities to reduce waste at source.

"We are also working on ways to further segregate the waste that is collected inflight - for example soft plastics and compostables.

'A major challenge we face, however, in reducing waste to landfill, is the lack of recycling and composting infrastructure available for us to send our material to.

'More robust infrastructure across the country, including in the regions, would help us keep compostables and recyclables out of landfills.

"Project Green is a very good example of the steps Air New Zealand is taking to build sustainability into its supply chain. We are looking to make impactful sustainability gains and, in order to do this, we have to enable those bigger conversations through relationships with our suppliers and business partners."