Residents of a Sydney apartment building have been left terrified after several huge cracks appeared in the roof and floor of their basement.

The cracks appear to be metres long in the Clemton Park Village apartment block, in Campsie, which is only three years old.

Footage shows multiple cracks in the roof, which is now jacked up with proofs and another huge crack on the floor of the basement.

The cracks appear to be metres long in the Clemton Park Village apartment block, in Campsie, which is only three-years-old

The horrific discovery comes a month after residents of the Mascot Tower were evacuated due to 'rapid deterioration'

The horrific discovery comes a month after residents of the Mascot Towers were evacuated due to 'rapid deterioration'.

'We're not sure if it's going to be the same, like what's happening in Mascot right now,' a resident told Seven News.

'We haven't been told much at all.'

The developer raised the alarm after one of the builders identified an issue with the concrete slab which was used for the apartment.

'As a precaution, temporary props were installed and engineers employed to confirm the property is safe,' the developer said.

Entrances and exits to the building have all been blocked with danger signs.

The horrific discovery comes a few weeks after residents of the Mascot building (pictured) were evacuated due to 'rapid deterioration'

Following the 'deterioration' in the Mascot Towers building, and the 'cracking noises' in the Opal Tower building, residents can expect to see people held accountable for these types of issues.

The NSW Government is implementing four key reforms to deliver a more robust regulatory framework for the construction of buildings.

'The legislation will implement many of the recommendations from the Lambert and Shergold-Weir reports into the building industry, and now we want to hear from industry and the wider community to help finalise the legislation,' Mr Anderson said.

'We are committed to getting these important reforms right and ensuring they are developed in close consultation with the industry and community.'