Twenty-two Sri Lankan monks returning from Thailand were arrested on Sunday at the main international airport with 110kg (242lbs) of powerful cannabis, officials said.

A Sri Lanka Customs spokesman said the group, returning home after a four-day holiday in the Thai capital, had kush – a potent, plant-based strain of cannabis – hidden in their luggage.

“Each carried about five kilos of the narcotic concealed within false walls in their luggage,” the spokesman said, adding that the monks had been handed over to police.

They were taken before a magistrate later on Sunday and ordered to stay in remand for seven days for further investigation.

The monks were mostly young students from temples across Sri Lanka and had been on a holiday sponsored by a businessman.

Three of the monks had recruited the rest via social media by promising them free airfare, accommodation and meals, according to Sri Lanka’s Daily Mirror.