Banning the consumption of alcohol on all public transport in the capital was Boris Johnson's first major policy announcement when he took office earlier this month.
However, a spokesman for the Mayor said: 'So far no case has been made for banning alcohol ads on the Tube, although all ads have to meet strict guidelines.'
CBS Outdoor, which sells the majority of ads on the Tube, counts alcohol advertising among its top-10 campaign categories on the Underground and one of the fastest-growing on its digital escalator-panels.
'The ban on drinking on the Tube is related to public safety and crime prevention,' said Tim Bleakley, managing director of CBS Outdoor. 'Advertising alcohol is an entirely different issue.'
There are a number of on-going alcohol ad campaigns on the Underground, including work for InBev's Stella Artois and Scottish & Newcastle's Jacques Premium Cider.