Leaping into the azure sea from a popular bayside cliff known as "the Pillars" will become a thing of the past, after a decision to close the popular Mount Martha bathing spot.

Mornington Peninsula Shire voted on Tuesday night to close the area to visitors and build a fence to stop the ballooning number of visitors, after the site reached prominence on international tourism sites.

Mornington Peninsula Shire mayor Bev Colomb said due to a jump in interest in the Pillars from social media, the site has been overused.

"It's a secluded, sensitive cliff area and there's no infrastructure or anything to support an environmental spot like that from the hordes of visitation," she said