The World Health Organisation has excluded two generic antiretroviral drugs of Indian-make from its list of approved HIV medicines used more often in poor countries, saying a routine check found that the manufacturer had not proved they were biologically equivalent to the patented drugs.

Indian pharmaceutical company Cipla, manufacturers of the drugs, however said that the problem was due to inadequate record-keeping in the testing laboratory in Mumbai, media reports said on Wednesday.

Cipla's Lamivudine, one of the affected drugs, has been tested for bioequivalency in a laboratory in the United States and approved by the Food and Drug Administration and the date would be submitted to the health agency, Cipla Chairperson Dr Yusuf K Hamied said.

Hamied said the testing was done for the American drug agency because Cipla hopes to sell generic Lamivudine when an American patent expires in 2006.

WHO did not announce the decision publicly after it was taken in May and its officials told the New York Times that such an announcement was not necessary because the agency had informed other United Nations agencies about the problem and had posted the delisting on its website.

It is the first time that WHO has removed any HIV drug from its list, Lembit Rago, an official of the Geneva-based agency, said.

The second drug pulled off the list is Zidovudine, which is also known as AZT. Cipla said the situation was "on the mend" and that it expected its drugs to be put back on the list within a matter of weeks.