Prime Minister Scott Morrison is seeking to head off criticisms of Australia's climate change policies by promising hundreds of millions of dollars to tackle the issue ahead of his arrival at a meeting of Pacific leaders in Tuvalu on Wednesday.

Key points: The money will also help improve infrastructure to withstand extreme weather events

The money will also help improve infrastructure to withstand extreme weather events Fiji's Prime Minister urged Australia to phase out coal-fired power generation

Fiji's Prime Minister urged Australia to phase out coal-fired power generation China is seeking to play a greater role in the PIF as a dialogue partner

He outlined $500 million over five years, starting in 2020, to help Pacific nations invest in renewable energy and 'climate and disaster resilience'.

But the money will be re-directed from existing aid programs, and is not additional support for the region.

In a statement, Mr Morrison said the funding "highlights our commitment to not just meeting our emissions reduction obligations at home but supporting our neighbours and friends".

"We're here to work with our Pacific partners to confront the potential challenges they face in the years ahead."

The money is aimed at helping Pacific countries invest in renewable energy, as well as improving infrastructure in roads, hospitals and schools to withstand extreme weather events.

'We face an existential threat'

Until Mr Morrison arrives, Australia is represented at the meeting by Alex Hawke. ( ABC News: Melissa Clarke )

While Mr Morrison won't arrive at the week-long Pacific Islands Forum (PIF) leaders meeting until tomorrow, many other heads of government are already on the tiny atoll that is home to Tuvalu's capital, Funafuti.

Fiji's Prime Minister Frank Bainimarama spoke at the climate change 'Sautalaga' (open discussion) held yesterday, seeking much stronger action from Australia, including phasing out coal-fired power generation.

"I appeal to Australia to do everything possible to achieve a rapid transition from coal to energy sources that do not contribute to climate change," he said.

"We face an existential threat that you don't face and challenges we expect your governments and people to more fully appreciate."

If sea levels continue to rise, the Pacific's food plantations may risk being destroyed due to saltwater intrusion. ( Oxfam: Rodney Dekker )

Mr Bainimarama welcomed efforts by Australia and New Zealand to improve relations with Fiji and the region more broadly, but that did not stop him pushing for them to do more domestically to limit climate change.

"I certainly look forward to seeing for myself, the progress Australia has made in managing the challenges of transforming its energy sector and integrating renewable energy when I make my first official visit there next month."

Until Mr Morrison arrives, Australia is represented at the meeting by Alex Hawke, Minister for International Development and the Pacific, who took part in a fatele (traditional dance) during last night's opening ceremony.

While prominent as the most senior member of the Australian delegation so far, Mr Hawke has appeared to be on the periphery of some informal discussions between prime ministers and presidents.

Australian delegation keeping an eye on China's influence

The funding promised by Mr Morrison will be re-directed from existing aid programs, and is not additional support for the region. ( ABC News: Melissa Clarke )

But Pacific leaders already in Funafuti appear more focused on making their case directly to their counterparts, Mr Morrison and New Zealand Prime Minister Jacinda Ardern, on Wednesday.

The PIF leaders meeting is expected to issue a consensus statement on climate change that will then form part of the United Nation's Climate Action Forum in New York next month.

The smaller Pacific states have been negotiating their own statement on climate change, with the hope of manoeuvring Australia into supporting a strong PIF statement to take to New York.

While Pacific states are focused squarely on climate change, the Australian delegation is keeping an eye on China's growing influence in the region.

China is seeking to play a greater role in the PIF as a dialogue partner, while Taiwan tries to ward off Beijing's efforts to upturn Taipei's diplomatic relations with half a dozen island countries.

Other countries from further abroad are seeking closer relations with the Pacific, with both Norway and Chile applying to become dialogue partners.