The first meeting of the committee on Wednesday came after early morning storms hit multiple areas of the state.
More storms are likely on Wednesday night and potentially Thursday morning.
Severe storms were detected about 5pm around the Blue Mountains and Hawkesbury-Nepean region to Sydney's west.
Storms were also spotted developing along parts of the Northern Rivers and Mid North Coast.
The Bureau of Meteorology warned damaging winds, large hailstones and heavy rain could accompany the storms through Grafton, Coffs Harbour, Port Macquarie, Taree, Sawtell and Dorrigo.
The SES, Rural Fire Service, Police and Resilience are the NSW government agencies attending the meeting, while the weather bureau has been invited as a guest.
The Bureau of Meteorology has warned flooding around the state could continue for months.
"With dams full, ground saturated and snowmelt over the coming weeks, even light to moderate falls may lead to renewed rises and additional flooding," the bureau said in a statement on Tuesday.
Deputy Premier Paul Toole says the committee and emergency agencies advising it will be pivotal to ensuring the state can respond to natural disasters, with potential for floods as well as fires in the upcoming summer.
"Every disaster, we learn from it, there are things that we do well, there are things that we can do better," he told the committee.
"This is about making sure we respond to support our communities across the state that have had a pretty rough time over the last couple years."
The committee was a recommendation of an inquiry into flooding in NSW earlier this year led by the state's chief scientist Mary O'Kane and former police commissioner Mick Fuller.
The committee will also address other elements of that inquiry, particularly those relating to whole-of-government disaster preparedness.
The review showed the government needed to be in a more permanent state of readiness to respond to disasters, Premier Dominic Perrottet said.
"This committee means boots on the ground and faster responses to protect communities in the event of a natural disaster in NSW," Mr Perrottet said.
The government has launched new warning systems, procured additional resources and will release further details on the long-term implementation of the inquiry's findings by the end of the year, the premier says.
Major flooding has been occurring on the Namoi River at Wee Waa, expected to last at least until Friday.
The Namoi could also deliver major flooding at Goangra next week as water heads downstream towards Walgett.
The Macquarie River fell below the major flood level at Warren on Tuesday afternoon after several days.
Major flood warnings are in place on the Namoi, Bogan, Lachlan, Culgoa, Birrie, Bokhara and Narran rivers.
The South Coast had the heaviest rain on Wednesday, Ulladulla receiving 45mm of rain in just over five hours.
Thursday is expected to be the wettest day of the week in Sydney and surrounds.
The rain should ease into the weekend but milder showers are likely to continue until next week.
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