Tribal chief Danny Ibang lived most of his life in the pristine jungles of the Malaysian portion of Borneo island until he was pushed into a modern world he was told would be better.

And in many ways, it is.

His Kenyah community of 2,000 enjoys electricity, running water, health and educational facilities previously undreamed-of since being moved out of the jungles to a new village to make way for the huge Bakun hydroelectric dam.

But as expanding dams, oil-palm plantations and other development forces thousands off ancestral lands in the state of Sarawak, a host of modern new problems threaten to break down once tight-knit tribal communities.

Village elders and activists say alcoholism, drug use, and crime are on the increase and anger is rising over continuing encroachment on native lands.

"There have been a lot of social changes after the Bakun dam," said Ibang, 66, whose people were among the first moved to the relocation village of Sungai Asap 14 years ago.

"Some teens who go to school learn to rebel against their parents, and boys and girls now mingle freely as they see it on the television," he said. There were 10 recent teen pregnancies -- something unheard-of in the old days.

The state government is pushing to develop the economy of Sarawak, which is blessed by rich natural resources yet remains one of Malaysia's poorest states.

But critics say the effort, while necessary, is plagued by graft and harms tribes that are ethnically distinct from the nation's majority Malays.

Tribal lands make up about 80 percent of Sarawak and "nearly all has been taken for logging and plantations", said Mark Bujang, head of Borneo Resources Institute, a body working in defence of native land rights.

In October, Penan tribespeople blocked roads into their lands for a week to protest logging and alleged river pollution by Malaysian firm Interhill until the blockade was dismantled by authorities.

At a forum on native concerns in the town of Bintulu in October organised by the Human Rights Commission of Malaysia, about 150 Iban tribespeople alleged a palm oil company illegally seized their land for a plantation and disturbed ancestral graves, said Joseph Laja, an Iban.

"We are really angry," Laja told commission members.

"If they move into another part of our land, there could be violence."

About four million of Malaysia's 28 million people belong to indigenous tribes, most of which are native to Malaysian Borneo where some retain diminishing traditional rainforest hunting and farming ways.

Officially, they enjoy the same preferential treatment in business, education and other areas accorded to Malays -- a controversial policy meant to lift Malay socio-economic standing.

But natives and activists say this has meant little to tribes, who remain among the country's poorest groups.

As a result, many youths welcome their new life and opportunities in Sungai Asap, which now has 11,600 people from a range of tribes living in traditionally inspired longhouses.

Roads linking the village to coastal cities have, along with modern telecommunications, opened new employment vistas for tribal youths.

"I love living in Sungai Asap," said Lenny Prescially, 18, as she tapped out messages to friends on Facebook in a local community centre.

Her family moved here from the jungles when she was four and she knows little of the old ways.

"Only the elders want to continue the old lifestyle. They don't know anything," she said dismissively of the older men who still hunt wild boar in forests and nearby palm plantations, machetes strapped to their waists.

The Bakun dam has been widely criticised as a white elephant, disastrous for uprooted tribes and pristine jungles that are now inundated by a reservoir the size of Singapore, its projected power output exceeding Sarawak's needs.

Transparency International has called the dam, which began generating electricity in August, a "monument to graft".

Much of the anger in Sarawak is directed at Chief Minister Abdul Taib Mahmud -- himself from the Melanau tribe -- who has governed the state since 1981 and is widely accused of corruption, cronyism, and plundering the state's resources, which he denies.

But Sarawak Land Development Minister James Masing said the state must develop the economy and give youths new opportunities.

"I have to support (the state's youths). We need to develop Sarawak," he told AFP.

But there is a palpable sense of rootlessness today for communities whose identity was long linked to ancestral lands passed down through generations.

"When our land is taken away, there is no longer any blood in our body," said Sungai Asap resident Stem Liau, 48.

Ibang, the Kenyah headman, said his people were promised eight hectares (20 acres) of farmland per family at Sungai Asap but only received a little more than one hectare of poor-quality land.

"Promises have been broken," said Ibang, who has struggled to grow pepper, cocoa and rubber.

Hasmy Agam, chairman of the rights commission, said it had received nearly 2,000 complaints over native land rights infringement in Malaysia over the past decade. Many of those complaining have threatened violence.

"We sense that. We hope that is not the solution," Hasmy said.