UPDATED 3.45pm: Work and Income offices in Linwood, Sydenham and Hornby in Christchurch were closed this afternoon after receiving threats.

The three WINZ offices in Christchurch have now been reopened.

It's understood the threats were made via the phone and police had been notified.

Riccarton Wigram Community Board Chairman Mike Mora said he was at the Hornby branch when it was closed.

He said there were "probably 15 people standing around the front of the building that had appointments. No security guard came out to talk to them at all, and they were just standing around there wondering what on earth was going on."

Mora said there wasn't even a sign to say what was happening.

Last year the Hornby office was closed after a 52-year-old man made threats against staff.

Threats against WINZ offices and staff are taken very seriously by Police, after two workers were fatally shot and one injured by Russell Tully in Ashburton in 2014.