More than 12,270 cartons of contraband cigarettes were seized last Friday - the third largest haul by Singapore Customs this year.

The total street value of the cigarettes and the total duty and Goods and Services Tax (GST) evaded amounted to more than $1.2 million and close to $1 million respectively.

Six men were also arrested in the raid at an open-air storage yard at Jalan Ahmad Ibrahim, the agency said in a statement on Friday.

Singapore Customs officers, working with the Immigration & Checkpoints Authority, discovered the contraband hidden in bulk liquid containers. These had been transported to the storage yard from Tanjong Pagar Scanning Station in two larger 20-foot containers.

The suspects - four Malaysians and two Singaporeans - face a minimum fine of $2,000 and $4,000 if it is their first or second tobacco-related offence.

Repeat offenders caught with more than 2kg of tobacco products also face mandatory imprisonment.