More than 150 homes were without electricity overnight after floods forced an energy company to cut supply in north-western Sydney.

Endeavour Energy cut power to around 160 houses along the Hawkesbury and Nepean Rivers which swelled after the Warragamba Dam opened its flood gates.

The company says it has cut the supply to protect emergency service workers and members of the public from electrocution.

'This is an important public safety initiative designed to ensure residents, our crews and emergency service workers can move safely in flood affected areas throughout the night and tomorrow,' a spokesperson for Endeavour Energy said in a statement late Saturday.

Almost 2000 people were told to evacuate from the area on Saturday.

Endeavour Energy said it will restore power to the homes as soon as it was deemed safe, but that would not be until at least Sunday.

'Electricity and water simply don't mix. Safety is our top priority and we must protect our workers and the public from the risk of electrical accidents,' the spokesperson said.

Copied from Sky News.com.au