Those who look younger than 40 will now have to produce their identification cards to prove that they are aged 18 or older before they are allowed to buy cigarettes or alcohol at 7-Eleven outlets.
Counter staff will then record their birth dates in the computer system. Anyone found to be under 18 will not be allowed to buy the items.
The trial, which began last week, is part of plans by Dairy Farm Singapore, which owns more than 530 7-Eleven stores, to stop underage youngsters from obtaining cigarettes and alcohol. 7-Eleven outlets in petrol stations are not included in the trial.
Previously, 7-Eleven staff asked only those who looked under 18 to produce ID to verify their age.
Responding to queries from The Straits Times, a Dairy Farm Singapore spokesman said the trial is part of constant reviews of its "systems and processes to further enhance regulatory compliance relating to sale of age-restricted products".
She added that 7-Eleven will review and finetune the beefed-up restrictions based on feedback from the authorities and customers.
7-Eleven's latest move comes on the back of the Government's fight against rising smoking rates and tobacco addiction among the young.
The number of daily smokers among young adults aged 18 to 29 stood at 16.3 per cent in 2010, up from 12.3 per cent in 2004, according to the latest numbers available from the 2010 National Health Survey. More under-18s, who are barred from smoking, have also been caught lighting up.
This trend comes despite years of efforts to stub out smoking through measures including high tobacco taxes, public education campaigns and stricter laws. Retailers caught selling cigarettes to underage smokers will have their tobacco retail licences suspended for six months the first time; subsequent offenders will lose their licences. This comes on top of a fine of up to $5,000 for a first conviction, and up to $10,000 for subsequent convictions.
According to reports by the Health Sciences Authority (HSA), four 7-Eleven outlets had their licences suspended for six months between 2006 and this year. Between January and October this year, 12 retailers were caught selling cigarettes to underage kids, said a spokesman for HSA.
Last year, 29 retailers were caught, down from 58 in 2011.
The spokesman said HSA welcomes 7-Eleven's "independent initiative", adding that the "continued cooperation of establishments which sell tobacco plays an important role in the national efforts to tackle the underage smoking problem".
Young people aged below 18 are also not allowed to consume or buy alcohol at any place licensed to sell alcohol - including bars, nightclubs and restaurants. The Home Affairs Ministry is now looking to ban alcohol consumption in common areas like void decks and parks, and reduce the number of hours during which shops can sell liquor.
7-Eleven's move to take down the birth dates of alcohol and cigarette buyers is backed by some experts who have called for cigarettes to be made a controlled item, like pharmaceutical drugs - meaning purchases are recorded.
Anti-smoking advocate Philip Eng said 7-Eleven's move is a "very small step forward" to weed out smoking. "It will make a difference if they can do away with the tobacco and stop selling cigarettes or at least remove them from the display counter," said Dr Eng, a consultant respiratory physician at Mount Elizabeth Hospital.
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