The people of Nelson are doing more than just helping the environment by recycling bottles - they are also laying the foundations for hosting matches in next year's Rugby World Cup.

The city's main rugby ground, Trafalgar Park, is undergoing a $5.9 million upgrade prior to hosting two cup matches, and is claiming a first in the use of recycled materials.

A "carpet" of recycled glass forms the base of the new turf, from which the grass will grow.

Nelson mayor Kerry Marshall, who poured the first bag of the sand, said the city was the first in New Zealand to use recycled material this way. "I hope we've set an example about good, sustainable practice ... Trafalgar Park will be an exceptional facility after this upgrade, but it'll be leading the country with its terrific new turf."

By using recycled glass sand, the dwindling natural resource of beach sand is not required. All but 5 per cent of the glass sand is used for the "sand carpet". Contractors then lay the grass seed with the remaining sand on top.

Over the next 20 weeks, the grass grows through and eventually roots down 10cm into the sand carpet.