Alcohol Concern has cited examples such as a Morrisons ad promoting lager brand Grolsch running during 'The Simpsons', and supermarket chain Lidl promoting its range of wines during 'Coronation Street' as examples.
Its study, based on monitoring alcohol ads for one week in 2006 and one week in 2007, also found that advertising rose during the 3pm-5pm time slot, when children are coming home from school and turning the TV on.
Srabani Sen, chief executive of Alcohol Concern, said: "A watershed ban is the only way to give parents the peace of mind knowing that their children can be kept safe from the influence of advertising."
At present, alcohol brands are not allowed to advertise during shows where children comprise more than 20% of the audience.
In July, a Commons motion was tabled by Labour MP Lynda Waltho calling for a 9pm watershed for alcohol ads, with Waltho claiming that "underage exposure to the promotion of alcohol is more dangerous than exposure to fast foods".
Bodies such as the Advertising Association and the Portman Group, the body funded by alcohol manufacturers to assist with self-regulation, strongly resist any further clampdown on advertising.
David Poley, chief executive of The Portman Group, said: "The advertising rules, which were toughened two years ago, ban adverts from targeting or appealing to under-18s.
"Shielding this age group from any images of alcohol is not helping them grow up with sensible and balanced attitudes to drinking."
Media owners also argue against such moves, fearing that if advertisers can only run ads during limited times, they may decide to abandon television altogether.