WELLINGTON, May 24, 2009 (AFP) - A powerful 6.1-magnitude earthquake rocked the remote Kermadec islands north of New Zealand Sunday, seismologists said.

The quake struck at 12:58 pm (0058 GMT), 270 kilometres (170 miles) south of Raoul Island at a depth of just 12.5 kilometres, the US Geological Survey said.

No tsunami warning was immediately issued.

Earthquakes and volcanic activity are common in the area, which is part of the "Ring of Fire" where the Pacific plate of the earth's crust meets other continental plates.

The Kermadec islands, 1,000 kilometres north of New Zealand, are uninhabited apart from Raoul, where New Zealand's Department of Conservation maintains a field station.