David Cameron has urged Caribbean countries to stop giving support to Argentine sovereignty claims over the Falkland Islands.
He told the Jamaican parliament it was time to "stand up for the rights of small islands" to self-determination.
The UK is unhappy that Jamaica and others have supported the position of Buenos Aires in regional groupings and at the United Nations.
Mr Cameron raised the issue with counterpart Portia Simpson Miller when they met for talks yesterday at her official residence in Kingston.
Addressing the parliament at the end of a short visit, Mr Cameron hailed the "shared values" of the UK and Caribbean nations, including democracy, human rights and "a rules-based international system".
"And standing up for the rights of small islands, including the Falklands, to enjoy the self-determination that has been so hard won in the Caribbean," he said.