Frantic search underway for missing snorkeller in Victoria

Water police and surf lifesavers are frantically searching for a snorkeller feared drowned in waters southwest of Melbourne.

The 21-year-old woman went missing just after 11am while snorkelling with a group near Altona Pier.

While authorities are unsure what happened, police snorkellers, surf lifesavers, jet skis and helicopters have spent the afternoon searching for the woman.

"Four of them went in and only three came out. We don't know what happened, it's just so scary for the parents," witness Sophie told 9News.

Despite the wind, the bay has remained flat for most of the day, however after heavy rain yesterday, the murky waters have made the search difficult.

Kane Treloar of Life Saving Victoria said this could be the state's 43^rd drowning since July last year.

"Which tragically is the highest number since detailed records have been kept, since the mid 2000's," he said.