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LONDON, June 23 (Reuters) - Amnesty International accused Tunisia on Monday of failing to curb torture of detainees held on suspicion of security and terrorism offences.

The north African country, a Western ally, said Amnesty's allegations lacked credibility.

Amnesty issued a report, "In the Name of Security: Routine Abuses in Tunisia" alleging specific cases of torture, including beatings, hoodings, sleep deprivation and electric shocks.

"The Tunisian government has repeatedly asserted that it abides by its international human rights obligations, yet this is far from the reality," an Amnesty statement said.

"It is high time that the authorities stop paying lip service to human rights and take concrete action to end abuses. As a first step, the Tunisian authorities must acknowledge the disturbing allegations documented in this report, commit to investigating them and bring those responsible to justice."

A Tunisian government official said terrorism was a serious challenge that the authorities were trying to address while abiding by national and international obligations.

The Amnesty report was subjective and lacked credibility, the official said.

"International Amnesty published (the statement) without taking care to verify the veracity of delusory allegations made by individuals known for their bias against Tunisia," he said.

The government would not hesitate to investigate and severely punish all proven abuses of power by police officers, including violence and mistreatment, the official said.

In one example cited in the Amnesty report, co-defendants Ramzi el Aifi, Ousama Abbadi and Mahdi Ben Elhaj Ali told their lawyers they were punched, tied up and kicked by prison guards at Mornaguia prison on Oct. 16, 2007, apparently because they had gone on hunger strike to protest against their conditions of detention.

The three were later jailed for security offences related to what prosecutors called an attempt to overthrow the government. Fourteen men were killed in clashes between police and a group of Islamists in Tunis suburbs in December 2006 and January 2007.

Tunisia, a country of 10 million, is the Maghreb's most Westernised state and President Ben Ali is credited widely with ensuring political stability and strong economic growth.

But rights groups accuse the government of running roughshod over human rights and democratic values, a charge the government strongly denies.

The government says it is committed to furthering democracy and respect for human rights, insisting critics of its rights record are biased and mirror the views of a minority of dissidents bent on smearing the country's image abroad.

In April, French President Nicolas Sarkozy dismissed concerns over Tunisia's human rights record, portraying its counter-terrorism efforts as a bulwark against the emergence of a "Taliban-type" regime in north Africa. (Editing by Giles Elgood)

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