Thousands more properties could now be caught up in Australia's cladding crisis, after authorities issued an alert warning against the use of another nine types of cladding.

Key points: The cladding products are commonly used on one and two-storey buildings

The cladding products are commonly used on one and two-storey buildings The Australian Institute of Building Surveyors has issued urgent advice to builders

The Australian Institute of Building Surveyors has issued urgent advice to builders A builder with 40 years' experience said he had "never seen anything as serious as this"

The alert will affect an unknown number of under-construction dwellings, including single-storey family homes, which had previously been largely unaffected but now may not be compliant with building codes.

Until now, most of the concern relating to non-compliant cladding was focused on flammable material used primarily on medium and high-rise buildings.

The decision, by Australia's leading building product accreditation agency, to withdraw support for the cladding materials has left industry experts stunned.

The Victorian Building Authority (VBA), which regulates the state's building sector, issued an alert on Wednesday afternoon stating that CertMark International had withdrawn nine certifications for cladding systems.

CertMark International is the agency that the Australian Building Codes Board (ABCB) relies upon to determine whether building products are compliant.

The VBA said that CertMark International had not clarified why it withdrew the nine certificates and the consequences of the decision were unclear.

"At this stage the ramifications of these decisions are unclear until we receive further information," a spokeswoman told the ABC.

When asked about the alert at a Senates estimates hearing, the Australian Building Codes Board's CEO, Neil Savery, did not explain the reasons for the move.

"The reasons why those certificates have been withdrawn by the conformity body varies quite widely," he said.

"It could be simply the case of inadequate documentation to support the certificate being issued."

Shortly after the estimates appearance, Mr Savery denied the move amounted to a ban.

"It doesn't mean the products can't be used, depending on the states and territories," he said.

"It's not retrospective."

In a statement, CertMark International said it understood the withdrawn certifications had caused "undue confusion", but that the changes were not retrospective.

"CMI understands that the withdrawal of these certificates has created undue confusion in the marketplace, espeically in relation to ongoing projects and assures all interested parties that the review and re-issue of these certificates is being given priority," the statement said.

"CMI wishes to advise that any projects completed prior to the withdrawal of the current certificates are still covered by the withdrawn certificate."

'The industry is falling apart'

The VBA alert said the certification withdrawal meant nine types of cladding "cannot be relied upon as evidence of suitability", meaning they may no longer be regarded as compliant with building codes.

The Australian Institute of Building Surveyors also issued urgent advice to building surveyors.

The organisation's vice president, Wayne Liddy, said the affected products were commonly used on small residential homes as well as high-rise apartments, meaning the impact would be felt throughout Australian cities and suburbs.

"It's very alarming," Mr Liddy said.

"It affects the industry as a whole. From high-rise to suburban housing.

"It's not just aluminium composite panel, or ACP, it's also expanded polystyrene, which is common in many buildings with fewer than three storeys.

"Many of these products thought to be compliant are no longer.

"We have buildings that we thought would be compliant using the regulatory system that we have, and now they're not."

Phil Dwyer, national president of the Builders Collective of Australia, said he had "never seen anything as serious as this" in his four decades as a builder.

He said the industry was trying to understand how the changes would affect builders who were doing the right thing and using approved materials.

"It's hit us between the eyes," Mr Dwyer said.

"We're in an incredible situation now where the industry is falling apart."

'A system of regulatory failure'

The national general manager of building inspection company Roscon, Sahil Bhasin, estimated the certification changes could quadruple the number of building rectification orders issued in Melbourne.

Banned cladding systems: CM40029 Ozone Panel Building Systems

CM40029 Ozone Panel Building Systems CM40066 Alpolic A2

CM40066 Alpolic A2 CM40067 Alpolic FR

CM40067 Alpolic FR CM40076 Ultrabond FR

CM40076 Ultrabond FR CM40079 Vitrabond FR

CM40079 Vitrabond FR CM40082 Dulux Exsulite TM Kooltherm Façade System

CM40082 Dulux Exsulite TM Kooltherm Façade System CM40093 Larson FR

CM40093 Larson FR CM40138 Dulux Exsulite TM Thermal Façade non-cavity system

CM40138 Dulux Exsulite TM Thermal Façade non-cavity system CM40162 Cladex FR

"The majority of second-storey dwellings in all the outer suburbs are built from expanded polystyrene," Mr Bhasin said.

"If you have a look at other places like Sydney's outskirts, they would also be affected.

"Unless these products can get a certification through another certifying body quite quickly then there'll be thousands more building orders that will be issued."

Mr Bhasin said the changes could also cause havoc for a cladding audit in Queensland.

"Queensland has been doing audits based on the combustibility of products," Mr Bhasin said.

"All [building] managers are required to submit a checklist online to say if they've got combustible products.

"What does a manager do based on this announcement? Do they still base [their response] on existing products? Or if they've already completed their checklist and submitted it to authorities, will they now get a reprimand and a fine?

"The penalties are quite severe in Queensland if you do not submit the appropriate information."

The issue of combustible cladding came back into the national spotlight this month, after fire spread up the side of a Melbourne apartment building. ( Supplied: MFB )

The issue of combustible cladding was thrust back into the national spotlight after fire quickly spread up the side of a Melbourne apartment building earlier this month.

Firefighters confirmed combustible cladding helped fuel the blaze, which spread from a balcony on the 22nd floor of the Neo200 building to the 27th floor.

The building had been deemed "medium risk" under the state's cladding audit, and had been issued with two show cause notices last year due to the combustible cladding.

Up until now, issues surrounding combustible cladding have been largely restricted to residential buildings above three storeys.

That is because the potentially dangerous products have been found on medium and high-rise properties throughout Australia, even though national building codes prohibit combustible materials from being used on the walls of residential buildings taller than three storeys.

"It's a system of regulatory failure," Mr Liddy said.