NSW's second inter-state disconnection from the power grid within three days due to bushfires has underscored the urgent need to beef up the power system to be able to deal with different threats across the system, not just high demand, Australian Energy Market Operator chief executive Audrey Zibelman said.

Ms Zibelman said the devastating bushfires that almost saw forced blackouts in NSW on Saturday showed the importance of a flexible power system where different resources could be called upon to in different situations to keep customers online.