The BBC's David Willis: "The judge warned people must be made aware that the issue is dealt with strictly in Singapore"

The pair, who are both in their twenties and engaged to be married, tested positive for the drug when they returned from studying in Australia - some three weeks later.

Gavin Seow Lek Chen, 28, and Lynn Cheok Lye Peng, 22, had smoked cannabis at an end of term party in the western Australian city of Perth.

They returned to Singapore to see their parents and failed a random drugs test as they attempted to enter the country - and were promptly arrested.

'Good students'

Passing sentence, District Judge FG Remedios told the couple: "All Singaporeans must be aware that consumption of drugs is dealt with very strictly here."

Their lawyer, Muralidharan Pillai, made a plea for leniency, saying they were both good students and pointing out that attitudes towards cannabis consumption were different overseas.

Singapore has some of the toughest drugs laws in the world. Drug trafficking carries a mandatory death sentence and even first-time Ecstasy users can face up to a year in jail.

Class A substance

The Straits Times reports that the couple, who had been living in Perth for over three years, went home to visit their families in late June. On 7 July, Seow went with Cheok and her parents for a holiday in Malacca and returned two days later.

The newspaper says the couple were stopped at the Tuas checkpoint and were asked to do a drugs test. Their urine samples tested positive for cannabis on the spot.

Further samples were sent off for testing, which confirmed the presence of a cannabinol derivative - a Class A controlled drug under Singaporean law.

Medical reports showed that Seow and Cheok were occasional cannabis users and that there was "little evidence" they were dependent on the drug, the Straits Times reported.