Canada Post has launched an investigation into why a community mailbox in Halifax was left open over the weekend, even after the Crown corporation was told twice by a neighbour who spotted the problem.

"This incident is absolutely unacceptable," spokesman Mouktar Abdillahi wrote in a statement to CBC News.

"We apologize and truly appreciate the diligence of the resident who contacted us, which is exactly what anyone with concerns should do."

Craig Potter spotted the problem Friday afternoon when he went to check his mail at the community mailbox on Stonehaven Street in the suburban Halifax neighbourhood of Armdale.

'Everything in this box is open'

The panel that gives postal workers access to all the individual mailboxes had been left ajar.

"Right now, everything in this box is open," Potter said in an interview early Monday afternoon.

"This is where the delivery person, you can see mail in here. The parcels, if there were any, would be available, someone's Mastercard statement, personal mail."

A total of 16 individual boxes and two larger slots for holding parcels were open.

Potter called Canada Post on Friday afternoon. When nothing had been done by Saturday morning, he called again. When the boxes were still open on Monday, he called CBC.

"It's disappointing to see the, I guess, lack of caring," Potter said.