WELLINGTON (AFP) - A 6.0-magnitude earthquake struck off the North Island of New Zealand on Saturday, the US Geological Survey reported, but there were no reports of any damage.

The quake struck at 0516 GMT (1.16pm Singapore time) was centred 204km deep and about 300km north-east of Auckland.

The tremor was not widely felt on the mainland, and police said there were no immediate reports of damage or injury.

A shallow 6.3-magnitude quake devastated New Zealand's second largest city of Christchurch in February last year, leaving 185 people dead.

The sparsely populated country 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.