The leaders of the Commonwealth group of nations will meet at a welcome banquet in Samoa in the South Pacific on Thursday, with climate change and reparations for Britain's role in the transatlantic slave trade on the agenda of summit discussions.

Leaders and officials from 56 countries with roots in Britain's empire, as well as Britain's King Charles, are attending the Commonwealth Heads of Government Meeting (CHOGM) in the small island nation, that began on Monday. The countries' foreign ministers also began a day of discussions on Thursday.

More than half of the Commonwealth's members are small states, many of which are low-lying island nations at risk from rising sea levels due to climate change.

United Nations Secretary-General Antonio Guterres has said ocean temperatures are rising in the Pacific Islands at three times the rate worldwide, and its population is "uniquely exposed" to the impact of rising sea levels.

"Climate change is an is an existential threat. It is the number one national security threat. It is the number one economic threat to the peoples of the Pacific and to many members of the Commonwealth," Australian Foreign Minister Penny Wong told a news conference after a meeting with counterparts.

A number of African countries, including Zambia, warned the meeting about the escalating impacts of climate change, including the effects on food security, she added.

On Thursday, Charles will be shown the impact of rising sea levels which are forcing people to move inland, a Samoan chief said.

Island leaders are expected to issue a declaration on ocean protection at the summit, with climate change being a central topic of discussion.

REPARATIONS PUSH

Also on the agenda is a push for Britain to pay reparations for transatlantic slavery, a long-standing issue that has recently been gaining momentum worldwide, particularly those part of the Caribbean Community (CARICOM) and more recently the African Union.

British Prime Minister Kier Starmer said on Monday the UK will not bring the issue of reparations for historical transatlantic slavery to the table at the summit, but is open to engage with leaders who want to discuss it.

CARICOM has set up a commission to seek reparations from former colonial powers such as the UK, France and Portugal.

Those opposed to paying reparations say countries shouldn't be held responsible for historical wrongs, while those in favour say the legacy of slavery has resulted in persistent and vast racial inequalities today.

A CARICOM source familiar with the matter told Reuters CHOGM presents an “important opportunity” for dialogue on reparations and the region will be tabling the issue there.

"It is a priority for many of the Commonwealth's member countries and whenever those affected by atrocities ask to talk, there should always be a willingness to sit down and listen," said Kingsley Abbott, director of the University of London's Institute of Commonwealth Studies, who is attending the summit.

From the 15th to the 19th century, at least 12.5 million Africans were kidnapped and forcibly transported by European ships and merchants and sold into slavery.

Those who survived the brutal voyage ended up toiling on plantations under inhumane conditions in the Americas, mostly in Brazil and the Caribbean, while others profited from their labour.