Pitcairn has become the second island in the region to pass a law allowing same sex marriage.
Guam became the first US territory to do so last month.
The British territory's Deputy Governor Kevin Lynch says the seven members of the Island Council unanimously passed the Same-Sex Marriage and Civil Partnership Ordinance last month after the British government requested it consult on the issue.
He says the move follows similar law changes in Britain and is a good thing for the island.
"I think it's quite a substantial change that reflects their standing in the world and bringing them into the line with modern legislation."
Kevin Lynch says he is not aware of any same-sex couples who would be likely to take advantage of the law change.