Some of the products, including Mie Sedaap Korean spicy chicken instant noodles, are being sold in Hong Kong. But it was not known whether affected batches have been delivered in the SAR.

The worry came a month after the Centre for Food Safety in Hong Kong recalled a batch of the Korean spicy chicken-flavored noodles after detecting the same pesticide in the product's seasoning and chili powder packets.

The Singapore Food Agency reported that affected batches included two types of cup noodles and four sorts of instant noodles.

All six batches of noodles were produced in Indonesia.

And the Thailand Food and Drug Administration also announced at the weekend that two batches of Mie Sedaap Korean spicy chicken noodles had been found to be contaminated with ethylene oxide.

Authorities in Singapore and Thailand have initiated recalls of the affected batches of the products.

In response to an inquiry yesterday by The Standard the Centre for Food Safety said that it was still conducting investigations into the matter.

"Upon learning about the incident through the Food Incident Surveillance System, the CFS has been contacting relevant authorities and major importers and retailers in Hong Kong to understand the situation," it said.

The center said it will continue to follow up on the incident and take action if appropriate.

The International Agency for Research on Cancer has classified ethylene oxide as a Group 1 carcinogen.

According to regulations governing products, food for human consumption that contains pesticide residues can only be sold if levels of not high enough to be dangerous and thus prejudicial to human health.

People convicted of flouting the regulation can be imprisoned for six months and fined up to HK$50,000.