DHAKA (AFP) - More than a thousand Bangladeshi children have been rushed to hospital after a spate of illness caused by anti-worm capsules and vitamin A given as part of an immunisation drive, officials said Monday.

But health department director Fatema Parvin Chowdhury told AFP that only 50 were "genuinely sick" while others had been taken to hospital by worried parents.

"So far over a thousand children came to government hospitals to seek treatment. But apart from a few cases, we found that most were gripped by panic," Chowdhury said.

Newspapers said hospitals in some towns had struggled to cope with the sudden rush of children on Sunday.

The drugs were given to some 20 million children in thousands of clinics and health centres across the country as part of a periodic immunisation drive against worms and malnutrition.

Angry parents blamed sub-standard drugs for causing nausea, vomiting and stomach pains. However, Chowdhury said the drugs were top quality.

"Some children who have worms could feel stomach pain due to the reaction of the anti-worm capsule. But it does not mean that they are sick," she added.

Health Minister A.F.M Ruhul Haque appealed for calm, telling parents and children that they have "no reason to panic."