A second Bay of Islands high speed jetboat operator has been ordered to pay fines and reparations after a passenger received serious spinal injuries during a sightseeing trip.

The woman was thrown into the air during a thrill ride with Mack Attack, owned by Seafort Holdings Ltd which operates off the coast of Paihia, on December 21, 2010.

Seafort was ordered to pay $30,000 in fines and $90,000 in reparations during sentencing in the Auckland District Court on Monday after being prosecuted by Maritime New Zealand (MNZ).

The company pleaded guilty to failing to take all practicable steps to ensure that no action or inaction of any employee while at work harmed any other person and failing to notify the director of MNZ about the incident as soon as possible.

The company's website says Mack Attack offers the fastest - up to 100km/h - and most spectacular way to see the Hole in the Rock in the Bay of Islands.

Mack Attack owner Richard John Prentice has also been charged in relation to an unrelated incident on January 2011. Mr Prentice denies the charge and is due to appear in the Kaikohe District Court on July 27.

Earlier on Monday Paihia-based Excitor III, owned by InterCity Group (NZ), was ordered to pay pay $270,000 in fines and reparations after three women broke their backs on sightseeing trips.

The company admitted two health and safety charges last month after incidents in January and March last year during trips out to the Hole in the Rock.

In the Auckland District Court on Monday the company copped fines of $120,000 and was ordered by Judge Phil Gittos to pay reparations totalling $150,000 to the three women.