The delayed salvage operation to cut the sunken Rena's accommodation block from the ship and raise it to the surface of the reef begins today.

Spokesman for the sunken container ship's owners and insurers, Hugo Shanahan, confirmed the cutting operation is starting today.

Barges at Astrolabe Reef as salvors work to remove part of the sunken accomodation block. Photo: Supplied.

The four-storey accommodation block is lying in water up to 50 metres deep, on the north eastern face of the Astrolabe Reef.

The containership Rena struck the reef on October 5, 2011 and later broke up. The remnant of the bow section was cut back to beneath the waterline by an earlier salvage operation. The larger stern section slid down the reef's slope into deeper water.

Resolve Salvage and Fire's plan is to cut the house free in two 350 tonne sections by the crane barge RMG500 and transfer to the deck barge RMG1000, which will be anchored near Motiti Island.

There are 500 metre exclusions zones round the two barges that will be involved in the operation.

Once cut, the two sections will be lifted onto the deck barge to be dismantled for scrap and, where possible, recycling. A team of small craft will be stationed at the reef to collect any debris released during the operation.

The temporary moving exclusion zone has been set around the barge transporting sections of the dismantled Rena accommodation block to the Port of Tauranga.

'The RMG1000 will be secured in place by four or more anchors, each marked with a large orange/yellow buoy and lit at night with a yellow flashing light,” says harbourmaster Jennifer Roberts.

'To ensure the safety of the divers and other workers involved in this operation, no unauthorised vessel may enter the temporary moving exclusion zone, the first of which extends out 500 metres from the barge RMG500 during the transit from Astrolabe Reef towards Motiti Island while transporting pieces of the Rena accommodation block.”

Anyone breaching the direction is liable to a fine or prosecution. The direction applies to all vessels, except those authorised by the harbourmaster or the duty salvage master.

The first temporary exclusion zone will be located around the barge RMG500 while it moves between Astrolabe Reef (37⁰32.4'S 176⁰25.7'E) and Motiti Island (37⁰37.5'S 176⁰25.0'E).

A second zone is around the barge transfer site near Motiti Island will be at one of the following locations, depending on the weather:

1. 37⁰36.745'S 176⁰24.166'E
2. 37⁰36.700'S 176⁰24.502'E
3. 37⁰38.117'S 176⁰26.169'E

A third temporary exclusion zone will also be located around the barge RMG1000 while it transits between the anchorage at Motiti Island (37⁰37.5'S 176⁰25.0'E) and the Port of Tauranga.

The direction remains in force until Rena accommodation block transfer and removal operations are completed, says Jennifer.