The Berejiklian government will issue warnings of potential threats to electricity supplies from next summer after its review of February's heatwave found the power sector to be vulnerable.

The initial report of its Energy Security Taskforce led by NSW Chief Scientist Mary O'Kane said the electricity industry was under strain during February 10's "hot day" when temperatures topped forecasts.

The unexpected loss of 1000 megawatts of gas-fired power capacity at two plants meant demand exceeded supply for 36 minutes during that afternoon – the first such shortfall in NSW since 2004 – and transmissions lines to Victoria and Queensland temporarily dropped below a secure operating state, the report said.

The government "as a priority" should refine emergency management procedures in case of a major blackout – noting such events are so rare as to be unpractised – and lead by example by introducing demand-management measures that would encourage consumers to curb power use when hot weather is predicted.