The owners of the Rena were today issued with two notices under the Maritime Transport Act.
Maritime New Zealand director Catherine Taylor declared the ship hazardous and instructed its owners to appoint a reputable salvage team.
The owners have selected international salvage company Svitzer to manage the operation, but Maritime New Zealand still has the power to take control of the operation if it is deemed necessary.
They must regularly update Maritime New Zealand on the salvage operation, both before a plan is put into action and once it is underway, and comply with all directions and inspection requirements.
Maritime New Zealand's national on-scene commander Rob Service said Svitzer was an internationally recognised and respected company with extensive experience in this type of operation.
Representatives from the company had been aboard the vessel since early this morning.
Planning for the salvage would be a slow and steady process and no plans had been made at this point, Maritime New Zealand spokeswoman Sophie Hazelhurst said.
"The salvage company is now working through a process, that's going to take some time. That's good by us - the last thing we want is for them to move too quickly and rush this,'' she told APNZ.
"The first step will be to assess the damage. That in itself is going to take quite a while, we've got a lot of damage to the vessel.
"They just have to take their time to really thoroughly assess that and look at how it's going to affect the overall structural integrity of the ship.''
Once the damage had been assessed, the salvage team would look at response options and start to form a plan.
"But I can't put a timeframe on it at this point.''
Meanwhile, there were concerns over a hazardous substance aboard the ship that could give off highly flammable hydrogen gas if it came into contact with water.
