Auckland, Feb 15 NZPA - The MetService omitted the word "thunderstorms" from a weather forecast on the day six students and a teacher died in a canyoning tragedy in the Mangatepopo Gorge in 2008, a coroner's inquest was told today.

Meteorologist Ross Marsden told the inquest a forecast was issued at 6.15am that day without the word "thunderstorms". It then issued a further forecast at 6.36am, but this one was not picked up by the Sir Edmund Hillary Outdoor Pursuits Centre (OPC).

Paul White, representing OPC, asked Mr Marsden if there was a procedure in place within the MetService to review a forecast after it had been sent out. He said there were such procedures in place, but OPC did not get the updated version.

Grieving families and a school are preparing for an emotional week.

The week-long inquest opened today with prayers in the Coroner's Court in Auckland.

The group from Elim Christian College in Auckland was swept away during an outdoor adventure course at the Sir Edmund Hillary OPC at Turangi in April 2008.

No criminal charges were laid over the incident but the OPC was last year ordered to pay $480,000 in fines and reparation after admitting two charges laid by the Department of Labour under the Health and Safety in Employment Act.

The department had said the OPC should have known from the heavy rain that the group should never have entered the gorge, even though the water levels were not high when they entered.

It also said the OPC should have either subscribed to the Met Service's weather warning service, or kept an eye on its website for weather warnings on the day of the tragedy.

Hastings coroner Christopher Devonport is holding the inquest to find out what caused the deaths.