The suspension came as the Industrial Works Department, the authority in charge of factories, ordered the pond to be closed for 30 days for improvement following an inspection of the site on Monday. Nikkei Asian Review reports that police are also investigating the case.

A CP Foods spokesperson said it is not clear whether the factory will be shut down for the whole 30-day period.

A 23-year-old university student, who was on an educational visit to the plant, died on Friday after falling into the 2.5 meter deep pond, according to local media.

Four factory staff who jumped in to rescue her died too.

Hydrogen sulfide, a poisonous gas that the waste water may have been producing in the confined space, may have been a cause of their deaths.

Although it is not yet known how the student fell into the pond, officers of the Industrial Works Department said there was no cover on the pond when they inspected the scene, suggesting that lax safety management could have led to the accident.

CP Foods issued a statement on Friday promising to pay out compensation of 3 million baht ($88,000) each to the families of those who died.

"We would like to express our deepest condolences and will be sure to take care of everything the best we can," Chief Executive Sooksunt Jiumjaiswanglerg said in the statement.

Shares of CP Foods closed at 25 baht, down 0.99 per cent from the previous session.