South Tarawa: Labor leader Bill Shorten has refused to back Pacific island calls for a moratorium on new coal mine development as he wrapped up a four-day tour of the region to highlight the impact of climate change.

Speaking in Kiribati, Mr Shorten said Australia would embrace stronger action on climate change under a Labor government but, when asked whether he would support the calls of some low-lying Pacific island nations to stop the expansion of coal, he said fossil fuels were still part of the world's energy mix.

The Kiribati President Anote Tong, whom Mr Shorten met on Tuesday evening, has led Pacific nation calls for a moratorium on new coal mines and the expansion of existing ones to be considered under a new global climate change agreement.

"I had long conversations with leaders of the Pacific nations about the future of fossil fuels and I made it very clear Labor is not going to stop coal mining," Mr Shorten said later when he landed in Townsville at the conclusion of the trip.

Mr Shorten went on to say that he thought the Pacific leaders he met had been heartened by the Labor delegation's visit to their nations and its focus on expanding renewable energy.

Prime Minister Malcolm Turnbull has also rejected similar calls, saying that if Australia stopped its coal exports it would not change global emissions "one iota."

As part of the tour, Mr Shorten, his deputy Tanya Plibersek and Labor's immigration spokesman Richard Marles visited Papua New Guinea, the Marshall Islands and Kiribati.

But the tour came with Labor not having yet fleshed out its climate policies.

In the lead-up to the next federal election, the Opposition has three pledges which it is still to provide detail on, including:

• Its proposed emissions reduction targets, which Mr Shorten has said would be more ambitious than the Turnbull government's promised 26 to 28 per cent cut to emissions by 2030 from 2005 levels
• The programs Labor would put in place to meet its proposed target of having a 50 per cent share of the energy mix for renewables by 2050
• The design of an emissions trading scheme the party is promising to introduce

On Wednesday Mr Shorten visited several hotspots in Kiribati, a nation of low-lying atolls spread across an area of the Pacific Ocean the size of India.

The tour took the Opposition Leader to causeways linking islets on the country's main island South Tarawa which have been battered by storm surges in recent times, causing the protective sea walls to break in places and the road to be washed over.

The Labor delegation also visited a stretch of beach where UN Secretary-General Ban Ki-Moon planted mangrove seedlings in 2011, an event which was attended by Mr Marles. The mangroves have since largely died off and a monument to the event has had to be moved further back up the beach.

Kiribati is regarded as one of the most vulnerable nations to climate change. In particular the atolls are struggling to keep salt water from inundating freshwater supplies and food growing land.

The problems are being exacerbated in some parts of the country by over-population, which has pushed residents closer to the shoreline and made other types of pollution like raw sewage worse. In some parts of South Tarawa, population density is great than in Hong Kong.

Hosting Mr Shorten at a dinner on Tuesday evening, Mr Tong said that he knew there was a view that over-crowding was linked to the problems of erosion and salt water inundation.

But he said in some of the outer, less-populated islands of his nation there were communities facing the same challenges, with some people having to leave their homes.

"The challenge that we are facing is threatening the very fabric of our lives and community and as a people," he said.

"I have been talking about these challenges for the last 10 years and I am continuing to ask myself why am I not being heard? Am I saying it the wrong way?"

Mr Tong welcomed Mr Shorten's trip, saying it had told his nation that there were people in Australia who care about the fate of Kiribati.

"So it gives us heart and it gives us greater courage to face what it is we must face in the years ahead," Mr Tong said.

As part of the visit Mr Tong said he wanted to share with the international guests his country's culture and way of life.

"So that when you go back to Australia you can say that 'this is something worth preserving, that we must try and do everything within our power to ensure it is maintained'."

Follow us on Twitter