Members of the public were turned away from the shop yesterday afternoon by a notice on the door advising them of the ''serious incident'' and advising them to use the Moray Pl branch instead.
However, the ''serious incident'' was only an IT misstep.
''The South Dunedin PostShop closed a bit early today because of a technical fault. The computers went down,'' New Zealand Post Group communications adviser Clare Pasley said.
''The fault was fixed this afternoon and the PostShop reopened at 4.20[pm].''
She could not comment on why workers at the shop had chosen to label the problem as a ''serious incident'', saying: ''I haven't got any information about that.''
Senior Sergeant Brian Benn said police sent a unit to investigate the matter but found the store open and running as normal.
Members of the public were puzzled by the closure and speculated as to the cause.
On social media, several people speculated that the serious incident might be a suspicious or dangerous package.
But workers at the store allayed their fears and conceded use of the serious incident sign ''might not have been appropriate''.
The store was expected to open as usual this morning.
