TEHRAN, April 14 (AFP) - Iran denied Sunday that it had stopped cooperating with a UN watchdog charged with verifying a worldwide ban on nuclear tests.

A spokeswoman for the Vienna-based Comprehensive Test Ban Treaty Organisation (CTBTO), said Friday that Tehran had stopped sending it data in January.

"The information is erroneous," Iran's permanent representative to the United Nations in Vienna, Pirouz Hosseini, was quoted as saying by the state news agency IRNA.

"The Islamic republic, one of the first signatories of the Comprehensive Test Ban Treaty, has always supplied data to the agency since the beginning of

The CTBTO, which has a global network of stations worldwide to verify that no nuclear tests take place, said the station in Iran, which began working in December 2001, had stopped transmitting information at the end of January.

CTBTO spokeswoman Daniela Roskonova said, "We were told by the Iranian authorities that the Iranian parliament started to ask itself whether it was a legal obligation to forward the data before the CTBT entered into force.

"We are not informed about any political reason for this decision," she added.

The 1996 treaty has still not entered into force and appears unlikely to do so in the near future, due to a crucial clause which requires its ratification by 44 nuclear-risk states.

Key countries on this list which have signed the treaty but not ratified it include the United States, China, Israel and Iran -- which Washington accuses of seeking to develop weapons of mass destruction -- while India, Pakistan and North Korea have refused to sign it.

Nuclear powers France, Britain and Russia have ratified the pact.

Iran's suspension does not endanger the effectiveness of CTBTO's monitoring network overall, Roskonova said, adding that monitoring stations in neighbouring countries could detect any seismic activity related to a nuclear test.

"Should anything take place in Iran we would know it immediately... We have stations elsewhere which can monitor Iran," she told AFP.