Bank staff 'sprayed with substance' in botched hold-up

A man has allegedly sprayed staff with an unknown substance in a failed bank robbery in Frankston.

The man stormed the bank on Young Street about 10.30am on Tuesday, a police spokeswoman said.

Police said he sprayed staff members before demanding cash.

He was arrested at the scene and is being interviewed by police.

Staff members were treated at the scene. They are not believed to have any serious injuries, the spokeswoman said.