The ad by Mother was released mid-April and showed a couple trying to replace their garden furniture only to encounter resistance from an army of angry gnomes.
The ASA received 49 complaints from viewers who deemed the ad offensive, unsuitable for children, frightening or violent. People also thought that children were likely to try and copy what they saw in the ad – gnomes being smashed to pieces.
A spokesman for the ASA said: "We take all the complaints we receive seriously. However, just because an ad has prompted a negative reaction amongst some viewers does not mean that we will automatically investigate. In fact, the Advertising Code even states that ads may be distasteful without necessarily breaking the rules on harm and offence.
"While we appreciated that the [Ikea] ad would not be to everyone’s taste we thought it was clearly fanciful and light-hearted. We also didn’t share the view that it would encourage or condone violence or anti-social behaviour and was unlikely to upset children […] It is not our role to act as censor. The garden gnome ad is a case in point."
A spokesman from Mother did not respond in time to comment.