Worksafe Victoria has confirmed it is investigating after suspected asbestos material was allegedly left unsecured near a childcare centre in Melbourne's west.

Key points: A CFMEU member spotted what he believed was broken asbestos sheeting in piles of construction rubble

A CFMEU member spotted what he believed was broken asbestos sheeting in piles of construction rubble The union advised a nearby childcare centre to keep the children indoors until further notice

The union advised a nearby childcare centre to keep the children indoors until further notice WorkSafe Victoria visited the site to ensure the materials were "appropriately managed"

A CFMEU member told the ABC he noticed what he believed to be large amounts of broken asbestos sheeting mixed into piles of construction rubble at Altona last Friday.

He said he immediately alerted workers at the Millers Road site and a nearby childcare centre.

The CFMEU said it had advised the management of the childcare centre that children should not play outside until further notice.

The union's Victoria occupational health and safety unit manager Gerry Ayers said he was horrified by the situation.

"In this day and age it is atrocious that cowboy operators can show such a blatant disregard for the safety of their workers and the general public," he said.

"We have advised the management of the childcare centre next door that children should not play outside until further notice, and that they register their potential exposure through the national asbestos, dust fumes and chemicals register.

In a statement, Worksafe Victoria said: "WorkSafe has visited the site to ensure the removal of any asbestos containing materials is appropriately managed."

The ABC understands the material, which may have been unsecured for up two weeks, has now been covered over.

The childcare centre has been contacted for comment.