The report has found almost 10 per cent of people aged 55 to 64 had 20 or more standard drinks in a week, compared to eight per cent of those aged 18 to 24.
But the survey found Australians were trying alcohol for the first time at a younger age.
The GSK survey questioned random samples of less than 100 people from each Australian state and territory.
Almost 11 per cent of the 18-to-24-year-olds surveyed said they were aged 12 or younger when they had their first alcoholic drink, while 42 per cent were between 12 and 15, the study found.
But only five per cent of 55- to 64-year-olds were aged 12 or younger and 17 per cent were aged between 12 and 15 at the time of their first tipple.
Government health guidelines recommend alcohol intake of no more than 20 standard drinks a week for men and no more than 10 drinks a week for women, GSK medical adviser Dr Eugene Goh said.
"Most of us associate heavy drinking with young Australians, but it appears some older Australians are indulging in unhealthy drinking habits as well," News.com.au quoted him, as saying.
"Older Australians need to watch their drinking and consult their GP if they are unsure how many standard drinks they can safely have in a week.
"They also need to be aware of the example they set for the young generation," he added.