Home Office minister James Brokenshire has urged operators to accept PASS (Proof of Age Standards Scheme) cards as ID for alcohol sales.
He said use of the cards does represent due diligence on behalf of the operator.
It follows recent reports that authorities in some areas have been reluctant to recognise the cards.
It's also been reported that doorstaff have been reluctant to accept PASS.
Brokenshire said: "The Government wholeheartedly supports the Proof of Age Standards Scheme (PASS), and would encourage all retailers to accept it as proof of age.
"Young people are rightly concerned about taking their passport with them on a night out, due to the risk of theft or loss, and they require a reliable document in order to prove their entitlement to purchase age-restricted goods.
"I am keen to reassure retailers that accepting a PASS hologram card which carries the bearers image and acceptable date of birth is due diligence, and can be accepted with confidence."
PASS chairman Robert Humphreys said: "This unambiguous clarification from the minister is most welcome and helpful.
"Retailers and their employees, including most especially door staff, should take comfort from it, and those who have felt any lingering doubt about whether or not they should accept cards bearing the PASS hologram can set them aside.
"The overwhelming majority of refusals of genuine PASS-hologrammed cards offered by young people who are of age to buy alcohol are by doorstaff, so I urge the trade to take this message to heart and to ensure that such employees are properly and fully trained to recognise and accept PASS cards.
"A third of the UK's 18 and 19 year-olds do not have passports or driving licences anyway, and many are keen to become your customers."