Gabon has restructured a small portion of its debt in return for $163 million in funds to protect its oceans, the government and an NGO said on Tuesday.

The debt-for-nature swap, covering about three percent of Gabon's debt, marks "the start of a 15-year conservation project... to help Gabon finance ocean protection and management for 30 percent of its ocean," said US-based NGO The Nature Conservancy (TNC).

Gabon's beaches and coastal waters are home to the world's largest population of endangered leatherback turtles, critically endangered Atlantic humpback dolphins, and one of the largest olive ridley turtle nesting sites in the Atlantic.

"For years we've been talking about green financing.. but there has been little action," Water and Forestry Minister Lee White told AFP.

"We hope this... small step ... will lead the way to new conversations," he said.

The debt conversion enables Gabon to refinance $500 million of its national debt in a way that secures funding for marine conservation activities and a clampdown on illegal fishing.

The deal involved the Bank of America issuing a new bond that is insured against political risk by the United States' International Development Finance Corporation, said TNC, an architect of the scheme.

"Our Blue Bonds programme (helps) governments reach their conservation and climate goals while also supporting the well-being of their people and economies," said CEO Jennifer Morris.

The new funds are designed to help Gabon improve the management of its territorial waters, 26 percent of which are currently earmarked as protected, and make its fishing industry more sustainable.

The small West African country is 88-percent covered by forest and has a vast coastline rich in marine species.

Its extensive mangrove forests represent one of the most secure carbon sinks in West and Central Africa, TNC said.