First it was supermarket bags, then it was drinking straws - now, will real estate signs be recognised as the next plastic menace?

One real estate boss thinks so, and has estimated a change could keep 37.5 tonnes of plastic out of New Zealand's waste stream each year.

Mike Pero Real Estate group is switching to aluminium composite "For Sale" signs, making them mandatory for all its agents from Saturday.

Owner Mike Pero has challenged other realtors to ditch the plastic.

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"Why wait for legislation when we can be proactive in bettering our environment?" he said.

Most 'For Sale' signs used in the real estate industry in New Zealand are made of corflute (corrugated) plastic. 

They typically cost about $10 each, and many are sent to landfill after a single use.

Pero said their new signs had a plywood base. They cost 10 times more than the plastic alternative, but reusing them will bring savings over time.

"It's definitely time now for us to fully get behind the call to reduce single-use plastic."

Real Estate Institute chief executive Bindi Norwell said that with 15,000 real estate agents working across the country, the industry could make a "significant contribution" by being more conscious of the environment.

Other real estate groups implemented measures such as reusing plastic in offices and were looking at recycling programmes, Norwell said.

Pero calculated that, with For Sale signs measuring half a square metre each and there being 75,000 property sales annually nationwide, the signs could be using 37,500 sq m of 5mm plastic each year.

This does not include signs for commercial leasing and rural sales.

"That's 37.5 tonnes of plastic, or the equivalent of six million plastic bags of unnecessary plastic a year.

"I also suspect my calculations are very conservative – it could be up to 10 million plastic bags a year," he said.

Pero said that while some real estate agencies do recycle their signs, many simply have new ones made because it's cheaper and more convenient.

"Everyone in the commercial, retail and services industry has a part to play in preventing unnecessary plastic waste, and this is ours," he said.

"It will pay in the long-run for our industry to do the right thing."