More than 3000 residents remain in limbo after being told to leave their brand new apartment block for a second time in four days.

More than 50 units in Sydney's cracked Opal Tower haven't been declared safe, and their tenants remain displaced.

Emergency services were called to the Opal Tower at Sydney Olympic Park on Monday after those living in the recently completed building heard and saw cracking in a wall throughout the morning.

Australia correspondent Murray Olds told Tim Dower furious residents will spend at least another 10 days away from home as engineers survey the building.

"You have mainly renters here. It is a brand new complex with apartments selling for over $1 million for a two bedroom place. The people have no idea when they will be allowed back in, residents are furious."

LISTEN ABOVE AS MURRAY OLDS SPEAKS TO TIM DOWER