Mauritian Prime Minister Paul Berenger is to meet the Commonwealth secretary general in London to discuss the sovereignty of the Chagos Islands.
Most of the evictees now live in poverty on Mauritius
Inhabitants of one of the islands, Diego Garcia, were evicted more than 30 years ago so it could be a US airbase.
A British court ruling in 2000 said the eviction was unlawful but a ruling in 2003 said there were no grounds for compensation or a right of return.
The 24-square-mile archipelago was separated from Mauritius in 1965.
At least 1,000 people were displaced from the archipelago between 1967 and 1973, to make way for the airbase.
Mauritius wants the archipelago returned and has not ruled out going to the United Nations over the case.
"The possibility that Mauritius will seek the backing of the UN to take the dispute to the International Court of Justice is also under consideration," a Mauritius government source told AFP.
Mr Berenger will speak to legal advisers in London and meet Commonwealth secretary general Don McKinnon.
Last month, Britain took steps to take full control of the immigration service of the islands, banning displaced islanders living in Mauritius or the Seychelles from visiting the archipelago.
Legal opinions from international lawyers say the decree which separated the archipelago from Mauritius was illegal because international law does not allow the dismembering of a country before independence.
The archipelago of 60 small islands has many natural resources and officials say use of the islands would be key to Mauritius' future development.
Officials say Mauritius could claim rent from the US for the use of Diego Garcia, exploit the archipelago's fishing resources and set up eco-tourism facilities.