Opposition lawmaker Son Chhay said yesterday he now plans to summon Minister of Mines and Energy Suy Sem for questioning in parliament after he failed to respond to his inquiry in writing regarding information on the export of silica sand.

Chhay, who is also planning to summon Labour Minister Ith Sam Heng, said the requests to appear for questioning will be delivered late this month when National Assembly President Heng Samrin returns from a mission abroad.

In a June 9 letter, Chhay requested Sem to provide information and documents related to silica sand extraction and exports, in response to revelations that the specific type of sand is exempt from a ban on sand exports.

“As principle, [Sem] must answer,” he said. “We have not seen his reply. So, it’s an abuse of the Constitution.”

Under the Constitution, a minister must provide a verbal or written response within seven days of receiving questions from lawmakers, Chhay noted.

Last year, the Mines Ministry temporarily suspended sand exports after controversy erupted over the discrepancy between the $5 million of sand exports to Singapore that Cambodia recorded from 2007 to 2015 and the $752 million that the city-state recorded as imports from the Kingdom.

Chhay also plans to summons Sam Heng – one of three ministers instructed by Prime Minister Hun Sen in February to ignore any requests by the opposition to appear before lawmakers at the assembly.

National Assembly spokesman Leng Peng Long said lawmakers have the right to summons government officials, but he said the questioning shouldn’t be used for “political gain.” In such cases, he said, the Assembly and Hun Sen would not allow the ministers to appear for questioning.

Chhay called on Sam Heng to appear in the National Assembly to answer questions about garment workers and migrant workers living in Thailand who weren’t able to travel to their hometowns to vote during the June 4 commune elections.

Dith Tina, a spokesman with the Ministry of Mines and Energy, said the ministry would respond to the opposition lawmaker’s inquiries, and that his questions required more than “simple answers that can be done within seven days”.