Speaking on the first parliamentary sitting day of 2020 on Tuesday, Mr Constance said "fire bombs" exploded in his community on December 31.

"That day on New Year's Eve has changed me forever ... it's hard, it's traumatic," he told the Legislative Assembly.

Mr Constance recounted the path of the blaze towards his Malua Bay property, south of Batemans Bay, and his attempts to spray his house with about 5000 litres of water before fleeing to the beach.

He made the late decision to leave when the fire's heat became too intense.

"I thought holy hell, we're going to lose hundreds of people," he said.

Mr Constance, who in January stepped aside from his role as NSW transport and roads minister to aid his electorate's recovery, pleaded with anyone impacted by bushfires to reach out for support.

"I don't want to see anyone on their knees fall through the cracks," he said.

Many NSW towns have lived under the threat of fire for months, with more than 2400 homes destroyed, five million hectares burned and 25 lives lost.

"These are really testing days. They are black days," Mr Constance said.

"It's a test of our humanity."

Mr Constance said he was more determined than ever to make the bushfire recovery the best the world has ever seen.

He urged his parliamentary colleagues to leave politics out of the process and focus on helping people and communities rebuild.

Mr Constance's wife Jen and his parents were in the chamber during his speech, which ended with a round of applause.

Premier Gladys Berejiklian used the day to move a condolence motion for those affected by the bushfires and allow MPs the chance to express sympathy for victims.

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Australian Associated Press