The Indonesian commercial attache has suggested corruption may be behind the incorrect labeling of oilfish that was subsequently sold in Hong Kong as codfish, causing several consumers to fall ill.
Haris Munandar said Tuesday there are several areas that need to be investigated.
These include the laboratory where the fish was labeled, the exporter, Indonesian government inspectors and the Hong Kong importer.
Munandar said an investigation is being conducted and that "if wrongdoing is verified, the Indonesian government will take stern action against those involved."
He said the Indonesian government has tightened its surveillance on the issuing of health certificates for exports, with all products being checked by the head of the respective laboratory before the certificate is signed.
ParknShop, meanwhile, said it is waiting for a report from the Indonesian consulate-general on the authenticity of the health certificate that it received before the oilfish saga blew up.
The consulate said it is waiting for the results of an investigation being conducted by the Indonesian Ministry of Marine Affairs and Fisheries.
Meanwhile, rival supermarket chain Wellcome, which receives its codfish from the same Hong Kong importer, has approached the supplier for clarification regarding the certificate it received.
Marketing director Diane Chiu Man said Wellcome is following up the matter with the supplier to ensure a similar situation does not arise again.
Wellcome, which has also discontinued sale of the fish, said it has received 380 complaints and inquiries, 370 of which have been settled through refunds.
Consumer Council chief executive Pamela Chan Wong-shui expressed concern over the limited labeling requirements and said the government should insist all food products be accurately labeled.
She said the council has received complaints from ParknShop customers and met with the supermarket chain to discuss refunds.
A spokesman for the Customs and Excise Department said that it has sought legal advice from the Department of Justice on whether the Trade Descriptions Ordinance has been breached.
The ordinance prohibits the application of a false trade description or trade mark to any goods and the supplying, importing, exporting and advertising of those goods.
"We will prosecute any supplier or person who has contravened the Trade Descriptions Ordinance if there is sufficient evidence," the spokesman said.
The department has conducted spot checks on supermarkets and frozen meat shops over the past three days.
"We have not discovered any cases of oilfish being labeled as codfish for sale during the observation checks," the spokesman said.
As of Tuesday, the Food and Environmental Hygiene department reported a total of 670 complaints and inquiries.
Oilfish is a member of the snake mackerel family and has a high oil content, which cannot be easily digested and may cause diarrhea.