According to media reports, Gillard's voice broke and her eyes welled up as she led condolence motions for the 35 people who died in the Queensland floods. Seven people remain on the missing list. The first day of parliament for 2011 has been set aside for the condolences.
She also paid tribute to all those affected by Cyclone Yasi and bushfires in Western Australia, where 68 homes were razed this week on the outskirts of state capital Perth.
"A new chapter in natural disaster history has been written", Gillard said adding, "you could not talk about the losses of summer in cold hard economic facts because human lives were immeasurable".
Recounting the difficulties Australia faced during the summer, Gillard said, "That is a cost that can't be measured. When people and communities were back to full strength the dead would not be forgotten".
"They are not just names on a list," she said. "They were someone's brother, sister, grandparent or child.
"No insurance payout is going to fill that," Gillard said. As she recounted the story of Jordan Rice, who was killed with his mother Donna, Gillard's usually controlled demeanour faltered.
The teenager had saved his brother's life instead of his own and was washed away with his mother. Gillard also spoke of a pregnant mother whose child was torn from her arms and drowned.
But in adversity came mateship and strength from volunteers and neighbours, the prime minister said. "We should also remember this summer as a sign of courage," Gillard said.
Gillard has been under sustained attack in recent weeks for her allegedly "wooden" demeanour when touring flood stricken towns.