A shallow 5.0-magnitude aftershock rocked the quake-hit New Zealand city of Christchurch on Monday, shaking items off shelves but not generating any reports of serious damage, officials said.

New Zealand's second largest city was devastated by a 6.3-magnitude earthquake in February which claimed 181 lives, and followed a stronger, but less destructive 7.0 quake last September.

The latest quake hit at 9:09 am (2109 Sunday GMT) and was centred 22 kilometres (14 miles) west of the city at a depth of just three kilometres, the US Geological Survey said.

New Zealand's GNS Science said the quake caused only minor damage.

Retail worker Jo Edmond told the Christchurch Press that stock fell from shelves in the Warehouse supermarket, near the tremor's epicentre, and she was feeling "a little bit nervous".

"The store's a bit of a mess. There's a lot of glass, but nothing too bad," she told the Press.

Christchurch was also hit by another smaller aftershock, measuring 3.7, about an hour before the 5.0 tremor, GNS Science said.

The city has experienced thousands of minor shakes since February's disaster and scientists said last week that there was an almost one-in-four chance of another quake measuring 6.0 to 7.0 in the next 12 months.

New Zealand sits on the so-called "Ring of Fire", the boundary of the Australian and Pacific tectonic plates, and experiences up to 15,000 tremors a year.