A Sri Lankan court remanded a senior cabinet minister in custody Saturday over the purchase of fake medicines for state hospitals when he was in charge of the health portfolio.

Former health minister Keheliya Rambukwella was ordered to be held until February 15 pending investigations into a 144 million rupee ($465,000) scam involving what were meant to be life-saving drugs.

Police told the court in Colombo the health ministry had intended to buy a stock of the antibody immunoglobulin, which is used on immune-compromised patients.

What the ministry paid for turned out to be mostly water.

"The drug had been issued to hospitals between July and September when patients reported adverse reactions triggering quality tests," an investigator told AFP.

It was not clear if there were deaths associated with the use of the fake medication.

The Criminal Investigations Department began questioning Rambukwella on Friday and took him before Colombo's Maligakanda Magistrate Court, where the judge ordered his detention.

Several other key health ministry officials have already been arrested. Rambukwella is currently the environment minister.

The supplier, a local company, was to be paid 960 million rupees ($3.1 million) but the payments were stopped after the quality concerns arose in September.

The owner of the company is also in custody.

Sri Lanka faced an acute shortage of medicines after the country defaulted on its $46 billion foreign debt in April 2022 after declaring bankruptcy.

Most essential medicines were later financed through a credit line from neighbouring India, as well as the World Bank.