How a mother's death from tsunami birthed an activist

The aftershocks and debris from the tsunami that killed her mother in Samoa reinforced the need for climate justice and Australia needed to heed the warnings of its Pacific neighbours, a new Greens senator says.

Former environmental lawyer turned Victorian representative Steph Hodgins-May has used her first speech in the Senate to call for more action on climate change after speaking with high-level officials in the region.

"My grief has largely clouded my memory of this trip but one memory that has stayed with me is of standing on the debris as aftershocks continued to shake the earth beneath my feet," she told the chamber on Wednesday.

"Local elders shared their stories, they spoke of the destruction caused by the tsunami - a freak, once-in-a-lifetime natural disaster, they hoped.

"But as I listened, the elders described the other compounding threats that extreme weather and a changing climate were having on their ability to survive."

Greens senator Steph Hodgins-May
Steph Hodgins-May brings experience as an environmental lawyer to her position in the Senate. (Lukas Coch/AAP PHOTOS)

She ended up helping Pacific island nations with climate ligation, including a request to the International Court of Justice asking for an advisory opinion on the climate change obligations of states.

"Their words reinforced to me that climate change is more than a matter of science, it's a matter of justice."

Vanuatu's climate change minister told her Australia's government needed to change and become more ambitious around climate targets, she said.

"I have great respect for the activists working across the environmental sector, the environmental lawyers ... but ultimately, this is where decisions are made," she told AAP ahead of her speech in reference to the Senate.

Labor legislated a net-zero emissions reduction target by 2050 and aims to reduce emissions by 43 per cent by 2030.

A more ambitious 2035 target will need to be unveiled under Australia's international obligations.

Senator Hodgins-May reiterated the Greens' call for no new coal and gas projects.

"That is resoundingly the call from the Pacific Islands," she said.

The Greens spokeswoman for early childhood education also used her first speech to call for it to be free and universally accessible.

She called for the scrapping of activity tests, where subsidies are tied to the hours a parent spends on certain tasks, calling them "punitive and cruel".

"People are having to make impossible decisions around whether to afford medicine, whether to pay their rent, whether to afford fresh groceries and then there's the cost of early childhood education and child care," she said.

Senator Hodgins-May replaced Janet Rice, who retired from politics, and was sworn in on May 14.