As an untouched West African paradise where hippos play in the Atlantic surf and buffaloes and elephants parade on the beach, little-visited Gabon had been marked out as a rising eco-tourism star. But foreign visitors may have to leave Africa's last Eden after the country's largest tour operator said it was abandoning its business there following a simmering row with authorities in the oil-rich nation.

Africa's Eden, the main operator in Gabon's showpiece Loango National Park, said that an ongoing dispute with the country's civil aviation authorities had forced it to pull out, closing the door on what it claims has been a €15m investment.

The acrimonious departure marks a sour end to initial efforts to rebrand the country as "Green Gabon". The former French colony has been trying to position itself as West Africa's answer to Costa Rica since taking the decision to allocate more than one tenth of its land to national parks in 2002.

Previously the sparsely populated equatorial country had been best known as a major oil producer, with President Omar Bongo – who ruled Gabon for 40 years until his death last year – connected with various alleged financial scandals involving French oil giant Elf. "Gabon without France is like a car with no driver. France without Gabon is like a car with no fuel," he once said.

The former French air force lieutenant was regularly criticised for flouting human rights and amassing a huge fortune in an impoverished nation. And the family's spectacular wealth was recently the subject of an embarrassing corruption probe by a French magistrate.

However, Mr Bongo attracted rare international praise eight years ago with his decision to gazette 11 per cent of the country for preservation in 13 national parks.

With some 70 per cent of forest cover and little in the way of infrastructure, the strategy depended on attracting comparatively small numbers of high-end visitors who could be flown to newly created lodges and camps inside the parks.

Evidence of progress in putting Gabon on the map came when Loango National Park was named in 2008 by the British Guild of Travel Writers as "best new overseas destination".

The income from tourism was then supposed to pay for the parks in a "cash for conservation" trade.

Gabon's promotion as one of the world's last true Edens – endorsed by several major conservation groups – was meant to be the beginning of an eco-tourism boom for the oil-dependent economies of West Africa.

Since taking over from his father, the country's new President Ali Ben Bongo has restated his commitment to developing tourism and insisted he believes in "Green Gabon". Now the falling out with the country's biggest tourism investor, Rombout Swanborn – the Dutch founder and CEO of Africa's Eden –threatens to unravel this strategy.

Mr Swanborn, who spent part of his childhood in Gabon and made his fortune in the oil industry, said he would be taking legal action to claw back some of his firm's losses on what had been billed as one of the world's most exciting eco-ventures. A spokesperson for the firm, Jacqueline van den Broek, said that Africa's Eden had stopped marketing the destination and would be closing up its exclusive Loango Lodge – and laying off 125 employees – when the current batch of visitors leave before the end of August.

She said that government talk of creating an industry had been let down by a lack of real effort on the ground: "After 10 years we're the only high end, professional operation in Gabon and we're being pushed out."

The final straw for the venture came after a year-long dispute with Gabon's much-maligned civil aviation authority. All Gabonese airlines have been blacklisted by the EU since 2008 after failing to meet 93 per cent of safety and operational requirements and the tour operator has its own in-house airline, SCD. But the authorities have refused to renew the operating licences. "We've been pushed to this stage quite a number of times but our patience has run out," said van den Broek.

Sebastiaan Verhage, who works in Gabon with the World Wildlife Fund (WWF) said the pull-out would be a blow for eco-tourism in the country but not necessarily a fatal one.

"Tourism is very important for Gabon and Africa's Eden are very important for tourism," he said by telephone from the capital, Libreville.

"They are the ones who got film stars and rich people to come here and made Gabon a bit more famous." But another five smaller operators are still in business, he added, and the southern sector of Loango park was still accessible even if the spectacular coastal area to the north was harder now to reach.

"This place is not going to become Costa Rica in the next few years. There are no roads, no hotels, no infrastructure for that," he said. "A real tourism boom could take 20 years or more."

Green Gabon?

* Former President Omar Bongo designated a staggering 11 per cent of Gabon's land mass a National Park – only Costa Rica has a higher proportion of the country given over to conservation.

* Established in September 2002, Loango is the jewel in the crown of the 13 parks. Situated between the Nkomi and Ndogo lagoons, forests, savannahs, wetlands and ocean all come together within its 380,000 acres. With more than 60 miles of uninhabited shoreline, it is widely regarded as one of Africa's last great coastal wildernesses.

* According to the Wildlife Conservation Society, up to 60,000 forest elephants inhabit the vast forests of Gabon. In Loango they can be spotted wandering the white sand beaches during the rainy season, which lasts from October to April.

* Gabon's beaches are home to the world's largest population of leatherback turtles, with a recent study estimating there are 47,000 females alone.

* After South Africa, the world's biggest concentration and variety (at least 14 at the last count) of whales and dolphins can be found off the Loango coast. Humpback whales head to Gabonese waters during their winter breeding season from June to September.

* Other species to spot include red river hogs, slender-snouted crocodiles, western lowland gorillas, manatees and a huge array of birds.

* Loango is also home to the legendary "surfing hippos". These were memorably captured on film frolicking in the warm equatorial waters of the Atlantic Ocean by National Geographic photographer Michael Nichols.

"The hippos feed all night and then came back surfing up the coast to sleep in the lagoon all day so I had to be there very early, ready to take pictures as they arrived," he explained. "That meant setting up camp at least 45 minutes away so as not to disturb them. I couldn't even use a flashlight because they might have seen it."

Nichols spent five months camping in the park with his family, as he documented the wildlife, much of which is unaccustomed to seeing humans because there are very few dwellings within the park. "It was a bit like the Beverly Hillbillies going to live on the beach in Africa," he said.