Australia must heed Pacific calls for a more ambitious climate strategy as the region faces an existential threat, a former environmental lawyer turned Greens senator says.

Steph Hodgins-May is due to deliver her first Senate speech on Wednesday after being sworn in on 14 May, replacing Janet Rice who retired from politics.

The Victorian senator was an environmental lawyer and worked as part of Australia’s mission to the United Nations.

Senator Hodgins-May later worked as Greenpeace Australia’s Pacific head and met with communities who expressed concern about the impacts of climate change and rising sea levels threatening their way of life.

She also helped 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.

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

“So that’s sort of when the penny dropped,” she told AAP ahead of her first speech.

“I have great respect for the activists working across the environmental sector, the environmental lawyers working with even those constrained legal frameworks, but ultimately, this is where decisions are made,” she said of the Senate.

Labour 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 death of her mother also drew her towards climate activism after she was killed by a tsunami in Samoa.

“So that kind of really jolted me into some sort of reality around do I want to be a corporate lawyer,” she said.

“I kind of stuck at it for a couple of years but quite quickly felt a pull back towards issues around climate justice in particular.”

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

Senator Hodgins-May has also 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.