KABUL - Corruption in Afghanistan has doubled in three years since 2006, despite pledges by the government to clean up graft in one of the world's poorest countries, according to a survey released Thursday.

Afghan President Hamid Karzai speaks after signing a decree at the Presidential Palace in Kabul in March 2010. Corruption in Afghanistan has doubled in three years since 2006, despite pledges by the government to clean up graft in one of the world's poorest countries, according to a survey released Thursday. (AFP/File/Shah Marai) Afghans paid one billion dollars in bribes in 2009, twice the value of those paid in 2006, according to Integrity Watch Afghanistan (IWA), a non-profit corruption watchdog.

In a poll of 6,500 Afghan adults, one in seven said they had experienced bribery, with more than a quarter of households saying they had paid a bribe to receive a public service.

It said corruption had become so entrenched that it threatened the multi-billion-dollar efforts of the international community to help end nearly nine years of current conflict, and rebuild Afghanistan after 30 years of war.

"The findings of this survey show that corruption threatens the legitimacy of state-building, badly affects state-society relations, feeds frustration and the support for the insurgency," IWA said.

Corruption also "leads to increasing inequality, impedes the rule of law according to Afghan standards, hinders access to basic public services, which impacts the poor most severely, and has a major negative effect on economic development," it said.

Corruption has been identified as one of the major problems plaguing Afghanistan as it tackles a Taliban-led insurgency that has spread across the country and intensified in recent years.

The United States and NATO allies are boosting foreign troop figures to 150,000 in coming weeks to escalate the fight in the Taliban's southern heartland and eradicate the insurgent threat in favour of civilian rule.

Key to the counter-insurgency strategy is winning the trust of ordinary people, assuring them that government officials are clean and judicial infrastructure accountable, which has not always been the case.

President Hamid Karzai is under intense pressure from Western backers that keep him in power to tackle corruption endemic in Afghan life, including in the polls that saw him re-elected last year to a second five-year term.

Earlier this year Karzai boosted the powers of the High Office of Oversight and Anti-Corruption, an anti-corruption body that had faced fierce accusations of being toothless and half-hearted in its battle to wipe out official graft.