LEIGH SALES, PRESENTER: When a cigarette was left on a balcony table in Melbourne's Docklands precinct last year, it took fewer than 15 minutes for 13 storeys to go up in flames. The problem was the cheap cladding that covered the entire apartment building. It didn't meet Australian standards and should never have been used. But since that fire, it's emerged that potentially thousands of buildings in Australia could be covered with the same material. Madeline Morris reports.

WITNESS: They came in and said, "Get out! Get out! Evacuate now!" Everyone was piling down the staircase and then we got outside and looked up and you could see the flames just pouring out of the building.

DAVID YOUSSEF, DEPUTY CHIEF OFFICER, METROPOLITAN FIRE BRIGADE: Those of us that have been around for 30 years or more have never seen a fire develop in this way. We never expected to see a high rise fire, particularly one in a new building, that would spread so quickly from the eighth floor to the 21st floor.

MADELEINE MORRIS, REPORTER: When the Lacrosse Building in Melbourne's Docklands district caught fire last November, it exposed a sleeping danger in Australia's booming construction scene: cheap cladding imported from China that is highly combustible and covering an unknown number of buildings in Australia.

MICHAEL O'CONNOR, CONSTRUCTION, FORESTRY, MINING & ENERGY UNION: It endangers the public, it increases the chances that someone's gonna be killed or someone's gonna be seriously injured and that's a concern for everybody.

MADELEINE MORRIS: So this is the cladding that was used on the Lacrosse Building. The brand name is Alucobest, but there are a number of different brands. On the outside, it's got aluminium, on the inside, it's got a polyethylene, or plastic, fibre. This is the cladding that should be used. It's called Alucobond. Aluminium again on the outside, but on the inside, it's got a mineral fibre core. But, to the naked eye, you would never know the difference.

Melbourne's Metropolitan Fire Brigade asked the CSIRO to test Alucobest's combustibility.

CSIRO REPRESENTATIVE: When we lowered the Alucobest in, because there's a polymer core to the sample, it started to flame at 55 seconds, so it is a combustible material.

MADELEINE MORRIS: 55 seconds to catch fire in a test.

This fire brigade animation shows how the fire, lit by a smouldering cigarette on the eighth floor of the Lacrosse Building, swept up 13 stories in as many minutes. It's running up the cheap, plastic-filled cladding.

MICHAEL O'CONNOR: This product is rife. It's used in buildings throughout Australia. All the information we're receiving, Brisbane, Perth, Melbourne, every capital city, we believe this product is used in many buildings and particularly in high rise buildings.

MADELEINE MORRIS: It shouldn't be. Building regulations prohibit the use of Alucobest cladding on high rise buildings. It is allowed on low rise buildings and that's why it's imported into Australia and easy to buy.

MICHAEL O'CONNOR: The material that's fire-resistant is a lot more expensive than the material that isn't, so if you're a builder and you see two different products, one's a lot cheaper and you get told that it meets Australian standard, you can't blame the builder for going for that product.

MADELEINE MORRIS: The problem is, surveyors may not know if builders have illegally used the flammable cladding on skyscrapers.

SCOTT WILLIAMS, CEO, FIRE PROTECTION ASSOC.: Quite often they're involved sometimes too at the end of the process, and when a building is built, as I said, and the product looks and feels the same, and unless they've got documentation and they've got evidence, really, they're just taking a guess.

MADELEINE MORRIS: And proper documentation about the materials used on buildings is frequently absent.

In 2011 the Victorian Auditor-General discovered 96 per cent of building permits issued by surveyors didn't have proper documentation, leaving "little assurance" surveyors were "adequately enforcing building and safety requirements".

WILHELM HARNISCH, CEO, NATIONAL MASTER BUILDERS ASSN OF AUST.: The buck has to obviously stop with someone, but finding out who that someone is is very complex in a legal context. Yes, the builders do have a responsibility, but so do the designers, so do the people who install it, so do the people who then finally approve it. So, you know, there are all these checks and balances all along the way.

MADELEINE MORRIS: The construction workers union says these checks and balances aren't being met.

MICHAEL O'CONNOR: When it comes to building materials and particularly imported building materials, it looks like no-one's in charge. So we have a flood of building materials being brought into this country, some claiming to meet Australian standards and we know they don't, some not even bothering to make a claim of meeting Australian standards. And when you go to the different authorities, whether it's the ACCC, whether it's the building code authorities, everybody's trying to say it's somebody else's problem.

MADELEINE MORRIS: Australia's not the only country to have problems with combustible cladding. This building in France and the ironically named Torch building in Dubai have also recently gone up in flames.

The challenge for fire fighters is hoses on ladders generally can't reach beyond the 20th floor and sprinklers are designed for internal fires.

DAVID YOUSSEF: Our concern is that if we get a fire on a number of levels simultaneously, which is the danger with this particular cladding, that the sprinkler system could potentially be overwhelmed and wouldn't be able to actually contain the fire.

MADELEINE MORRIS: Officers from Melbourne's Metropolitan Fire Brigade are now going around the country teaching of the danger of combustible cladding. Fire prevention industry leaders warn that until every building with combustible cladding is identified and dealt with, apartment owners could be sitting on a time bomb.

SCOTT WILLIAMS: We've dodged a bullet in this particular situation. We've been very lucky - we're lucky that in this case the fire services, the Metropolitan Fire Brigade, were able to evacuate all people. We're very lucky this building was only 21 storeys high, but the fire raced up the outside.

LEIGH SALES: Madeleine Morris reporting.