Five people complained that the campaign’s strapline: "For people who don’t like water" would wrongfully discourage young people from drinking water in favour of fizzy drinks, which is detrimental to their health.
Coca-Cola, the owner of Oasis, said it did not feel the ad discredited water, rather it promoted choice.
It said the ad was intended to be viewed as tongue-in-cheek and was aimed at a twentysomething audience.
The advertiser added that it was not advocating poor nutritional habits and that Oasis was a low-calorie drink which, if consumed in moderation, could not be considered detrimental to health.
The ASA noted the animated, fantastical environments depicted in both ads and said that the ads were intended to be comical and surreal. As a result, the watchdog concluded that the ads were not harmful.
No further action was necessary.