The state government is scrambling to ensure the "structural integrity" of several high-rise buildings in the Sydney Olympic Park precinct after cracks in Opal Tower forced hundreds of residents to evacuate on Monday.

The building fault, reported by residents who heard "cracking noises", caused the 36-storey tower to move up to 2 millimetres and left doors jammed shut.

While most of Opal Tower's residents were eventually allowed to return home on Monday night, occupants of 51 apartments were forced to spend Christmas Eve elsewhere and have not been allowed to return.

Planning Minister Anthony Roberts' department will urgently investigate "what steps were taken to ensure the structural integrity of that building and other buildings at Olympic Park", his spokesman said on Tuesday.