NSW Rural Fire Service commissioner Shane Fitzsimmons will step down just months after leading the state through the horror bushfire season to head up a new disaster and recovery agency.

Mr Fitzsimmons, 50, will retire as boss of the fire service this month and, from May 1, will become the first commissioner of a new agency to be known as Resilience NSW.

NSW RFS commissioner Shane Fitzsimmons will step down to take on a new role. Credit:Cole Bennetts

Resilience NSW will be responsible for "disaster preparedness and recovery" for NSW in the wake of the bushfires, drought and the worsening coronavirus health crisis.

Premier Gladys Berejiklian will announce the new agency on Monday.