L'Oreal heiress Liliane Bettencourt, France's richest woman, has sold a string of private islands in the Seychelles to a firm linked to an ocean conservation foundation, a minister said Tuesday.

Bettencourt, 89, bought D'Arros Island along with several neighbouring islets for $18 million in 1998 and recently sold them for $60 million (74 million euros) to a Seychelles-registered business, Housing and Habitat Minister Christian Lionnet said. He did not say when the sale was completed.

The stunning islands are located in the Indian Ocean, about 250 kilometres (155 miles) southwest of the main Seychelles island of Mahe.

The Seychelles-registered business that bought the islands is called the Chelomia Company Ltd, which is affiliated with the Geneva-based Save our Seas foundation, officials said.

Attempts to reach Save our Seas, which has an offshore account in the British Virgin islands, for comment were not immediately successful.

The Seychelles government said in a statement that the islands would "soon be proclaimed a nature reserve" and "managed by the Save our Seas Foundation in direct collaboration with the Ministry of Environment and Energy."

According to its website, the Save our Seas Foundation was founded in 2003 and "is committed to protecting our oceans by funding research, education, awareness and conservation projects".

As part of the sale, Bettencourt agreed to pay $8 million to the Seychelles state that were due in 1998 after she bought the islands but were not paid at the time, Lionnet added.

The Seychelles also collected an additional $10.5 million in taxes from the newest sale of the islands, he said.

Bettencourt was the target of a French tax probe but tax authorities said last year they would not pursue criminal charges against her.

During the probe, she revealed more 100 million euros in undeclared funds in a dozen bank accounts including in Switzerland and Singapore, as well as the island property in the Seychelles.