Hundreds of residents evacuated from a 27-storey high-rise in Melbourne's CBD will be locked out of their apartments for days, after a burst pump flooded the basement cutting power to the building.

Occupants of Liberty Tower's 237 apartments were told to leave late Sunday night because the flooding had cut power throughout the building and damaged the lift.

Businesses on the bottom level of the building have had to close due to the lack of power. Credit:Chris Hopkins

The water was up to 1.5 metres deep in some areas of the basement, before police were called to help residents evacuate the building on the corner of Collins and Spencer streets.

The tower was declared temporarily uninhabitable by Melbourne City Council about 11pm on Sunday, just as the city's temperature plunged below 10 degrees.