Senior Constable Murray Hewitson, of Owaka, said the latest theft happened sometime at the weekend at Purakaunui Bay.
Someone had cut through the padlock on the camping honesty box and taken the money in it.
He estimated between $600 and $1000 could have been in the box.
The box was last cleared by the Department of Conservation on Friday.
Snr Const Hewitson suspected the device used to cut through the padlock would have been some form of modern slim handsaw or cutting device able to reach into the honesty box.
''It wouldn't be a two-second job to cut through that, I wouldn't think.''
Snr Const Hewitson said there was a lot of people at Purakaunui Bay over the weekend and he believed someone would have seen something.
''It [the honesty box] is right in front of everybody because it's where they camp.''
He said at least 40 people were camping there.
The money in the box would have also been in separate small bags.
Another honesty box at Tawanui was broken into the weekend before.
There was a possibility other honesty boxes had been targeted in the South Island as well, he said.
If anyone had any information in relation to the thefts they were asked to contact police.
''If they saw somebody hanging around there or know of anybody with a decent amount of ... money in bags.''
Balclutha Police, 03 418 0203; Crimestoppers, 0800 555 111.
