A entire unit block is in danger of collapsing after it was ripped apart by a suspected gas explosion in a second-floor apartment.

The blast at 6.30am on Friday destroyed both the inner and outer brick walls of a unit in a three-storey block on Clarence Street in Lidcombe, 15km west of the CBD.

Locals said they feared a bomb had gone off, and emergency services found part of the building blown out, with debris strewn onto the street and vehicles below.

Nine people were injured. NSW Ambulance told Daily Mail Australia that two people were taken to hospital.

A man in his 40s was transported to Westmead Hospital in a serious condition with burns to his hands and face.

Another man, in his 60s, was taken to Auburn Hospital suffering from smoke inhalation. The other seven victims – five adults and two kids – were assessed by paramedics at the scene. Four nearby buildings were evacuated.

Engineers have now deemed the whole building unsafe. Residents were briefly allowed to enter to get some belongings but now face weeks locked out their homes.

Neighbour Pabita said she was in the shower when she heard the massive explosion.

‘I was just scared because there was a big, loud sound in my room – like a bomb blast,’ she told Daily Mail Australia.

‘It was scary, and after I got out of the shower, I checked every room, but they had already evacuated the building. We’re still not allowed to go back inside.’

Fire and Rescue NSW Superintendent Adam Dewberry said residents evacuated after the explosion, but specialist rescue crews remain on site to locate those still unaccounted for.

‘What we’ve had is an explosion in a unit on the second level of a three-storey block, which has literally blown out both the inner and outer brick walls,’ he said.

‘Thankfully, the floors – which are concrete – appear to be stable, as it’s a more modern-style building.

‘We’ll have about 18 fire trucks on scene. We’ve just evacuated the complex. There are a number of other buildings in the complex that haven’t been impacted, but we’re checking them as a precaution.

‘We don’t yet have an ‘all clear’ – which means we can’t confirm everyone is accounted for or that there are no further injuries – but that’s what we’re working towards now.’

Gas and electricity have been turned off at the scene to minimise any risk of further damage.

NSW Police Superintendent Robert Toynton said initial investigations had already ruled out any suspicions of a drug lab operating in the apartment. 

An evacuation centre at Burella Community Centre has been set up and 11 people were expect to take refuge there tonight, he added.

But residents could be locked out for some time.  

‘I’m hopeful by lunchtime the adjoining buildings will get some sort of indication as to a time [to go back in],’ he said.

‘But the affected building does have significant damage to it so that’s a challenge.’

Puja Shrestha, 23, lives in the apartment below the destroyed unit and relived the moment it exploded.

‘It was like a bomb blasted or something,’ she told Daily Mail Australia.

‘After a few seconds, the bricks exploded. We checked from the window and we saw the car (below) crushed by bricks.’

She said there had been no indication of when she would be allowed back into her home.

‘Police haven’t told us about how many days, but they also explained they need to check whether it’s safe to stay or not,’ she said. 

‘Today they will allow us to be at the community centre to help us with accommodation so we are relying on that.’

Ms Shrestha said she now faced a nightmare trying to get on with everyday life while locked out of her home, and admitted she was ‘a little bit sad’.

‘We need to go out to work as well,’ she said. ‘I don’t know what’s going on and how we can go.’

Police have established a crime scene, but structural engineers will need to survey the building before officers can go in for a proper investigation.