A tale of detailed planning, surveillance and split-second timing was revealed to the Wellington District Court yesterday when two men admitted their part in New Zealand's biggest robbery.

About $940,000 was seized from two Chubb security officers in a robbery in Willis St, Wellington, on December 22.

Jonathan Robert McDonald, aged 27, of Upper Hutt, and Quintin William O'Brien, 23, of Stokes Valley, both unemployed, pleaded guilty to joint charges of being party to aggravated robbery and unlawfully taking a motor vehicle.

In a lengthy summary of facts, police prosecutor Sergeant Marc May outlined to the court the planning, preparation and execution of the robbery.

He said planning began about last April, and over the next seven months those allegedly involved, including McDonald and O'Brien, were recruited.

In the months leading up to the robbery, the gang met and discussed various issues, including obtaining disguises and clothing like that worn by the security guards.

Members of the gang also had mobile phones with numbers that had been pre-set for communication between them on the day of the robbery, Sergeant May said.

McDonald, O'Brien and three others were responsible for ascertaining the exact movements of the guards. They watched them from various observation points for several weeks.

About six weeks before the raid two other gang members discovered the Kaiwharawhara powder magazine in Ngaio Gorge and decided to abandon the Chubb van there.

McDonald also had the task of buying abseiling equipment needed by the gang to get down a steep concrete wall to reach the back of the automated teller machine.

The gang completed several dry runs of the whole heist, testing timing and ensuring that each person was in the correct place and could complete his tasks.

Late on December 21 four of the gang met McDonald at his house and about 3.30 the next morning he drove them to Boulcott St. He waited in his car while three of them, carrying their weapons, equipment and disguises, abseiled down the concrete wall behind the money machine, then scaled another wall into the yard behind the ATM.

McDonald dropped his car along the route that the van was to take after the robbery, then was himself dropped off at the Kaiwharawhara magazine. He wore overalls and earmuffs to look like a Wellington City Council worker, Sergeant May said.

The other man continued to the city, where he parked his car and walked to Willis St. The gang was now ready for the heist.

About 6.25 am the Chubb security van was loaded with 32 cash canisters and cash orders for Porirua and Kapiti businesses. In total it carried $940,404.

As the van passed one of the gang stationed in Petone, he called to alert O'Brien, who was parked in Featherston St.

From there he could watch the van make its first stop in Lambton Quay. O'Brien called the next person to say it was on its way, then drove to Sar St, Thorndon, where he could watch traffic leaving Tinakori Rd.

About 7.30 am the van arrived in Willis St and parked opposite the money machine. The two guards got out with four canisters of money. The waiting robbers were telephoned to tell them the van had arrived.

The guards walked down an internal passage way and unlocked two doors to get to the yard at the rear of the machine.

There they were confronted by three men. They were told to get on the ground and had tape put over their eyes and mouth and around their wrists and feet.

The three allegedly took the van keys and the money from the canisters before leaving. Two of them got into the security van, the other met up with a fourth man.

As the van came off Tinakori Rd, O'Brien was signalled to pull out behind it. His job was to slow traffic going up Ngaio Gorge to give the van time to pull into the magazine without being seen by other motorists. Another man was given the job of slowing traffic coming down the gorge.

At the magazine, McDonald received a call and opened the barrier arm to let the van through, before locking it and throwing away the key. He shut the magazine's roller door once the vehicle was inside.

Two backpacks were stuffed with cash and disguises, but several canisters of cash had to be left behind.

McDonald and the other two ran up a track to the Trelissick Park car park where two gang members were waiting in two cars. Alerted by a phone call that police had set up a cordon on the motorway cutting off the escape route to their safe house, the gang took the money to a house in Porirua.

That afternoon some of the money was divided up. McDonald was given $10,000 for his part. Later that day the money was hidden in a wardrobe at O'Brien's house. He was also given $10,000, Sergeant May said.

When spoken to by police, McDonald and O'Brien were cooperative and admitted the part they had played.

They were convicted and remanded for pre-sentence and reparation reports. They will be sentenced on March 2.

Two other men appeared yesterday on charges of aggravated robbery and unlawfully taking a motor vehicle. Former security guard John Ruahina Moeke, 25, of Upper Hutt, and Wayne Turner, 25, unemployed, of not fixed abode, were remanded in custody until March 19.

Two other Upper Hutt people facing charges of aggravated robbery and unlawfully taking a motor vehicle also appeared yesterday.

Samantha Gay Roser, 26, a beneficiary, was remanded in custody for a hearing on March 19, and Peter Richard Tyson, 25, a former security guard, was remanded in custody until February 19.