Hundreds of schools across Australia and New Zealand have in recent days been scrambling to check whether they were using the tainted products.

Forty schools and daycare centres had been closed in New Zealand as they tracked down and removed the decorative sand, an education ministry spokesman said.

More than 70 schools were shuttered in Australia on Monday.

New Zealand's workplace safety regulator said batches of the play sand were contaminated with chrysotile asbestos.

"This sand product is allegedly imported from China and can be used in classroom activities, as well as other decorative and craft uses at home," WorkSafe New Zealand said.

Asbestos is a naturally occurring mineral fibre that was once widely used for construction because of its heat-resistant properties.

But studies have found a clear link between lung cancer and long-term exposure to chrysotile asbestos fibres.

Asked about the recent cases in Australia and New Zealand, Chinese foreign ministry spokeswoman Mao Ning said Beijing had "noted the relevant reports".

"We... also noted that local Australian businesses have stated they are communicating with suppliers to resolve the issues," she told reporters at a regular briefing.

Australia's product safety watchdog said the risk was low as tests had so far not detected breathable fibres.

"The release of respirable asbestos fibres is unlikely to occur in its current state, unless the sand is processed by mechanical means such as crushing or pulverising," it said.

"The risk that any asbestos found is likely to be airborne or fine enough for inhalation is low."