A tsunami potential threat advisory is now in effect for New Zealand following a powerful 8.9 earthquake off the coast of Japan this evening.

The advisory will remain in effect until it is upgraded to a national warning or a cancellation message is issued by the Ministry of Civil Defence & Emergency Management (MCDEM).

Gut wrenching footage of a huge wave slamming Japan’s coast is being aired on all the main international news networks.  Cars racing to get away from the wave have been engulfed.  Homes and large buildings flattened in seconds, some exploding into flames.

The death toll is likely to be high judging by the footage.  The wall of water, estimated to be between 7 and 10 metres high is still moving down the coast and across the Pacific Ocean at the speed of a 747.

We will bring you updates all evening – for those with Sky we suggest CNN on channel 91.

For those who do not have satellite TV you can view online here via Aljazeera: http://english.aljazeera.net/watch_now/