The ship grounded on the Astrolabe Reef appears to have stopped leaking oil, but there is estimated to be 10 tonnes of oil in the water.

Maritime New Zealand released a statement this morning saying aerial observation flights of the Rena wreck and oil slick showed intermittent leaking appears to have ceased.

Workers load equipment onto one of the vessels preparing to commence a clean-up this afternoon.

At the Port of Tauranga, the on-water recovery operations manager Mick Courtnell is coordinating two vessels and crews to commence a boom operation this afternoon.

He estimates only a small amount of the oil can be recovered today and is satisfied with the pace his team is working at.

'We are not looking at spilt milk in the kitchen – we are dealing with a large, difficult problem.”

The equipment is being trialled and the crews are being trained in the harbour to set clean-up parameters and ensure safety.

'If we lost someone owing to bad planning it may very well become a bigger story than the oil spill.”

On-water recovery operations manager Mick Courtnell says his team is working as best they can in a situation no-one wants: 'It's a damned shame it's in New Zealand's backyard.”

There are also logistics to manage and Mr Courtnell says rushing out with booms is not an effective or efficient approach.

'Before we can do on-water recovery we need something robust in place to deal with the oil when it comes back.”

There are also environmental concerns with all craft involved in a boom operation sure to draw significant amounts of oil on them.

Their movement would then spread the oil outside the slick site making the overall clean-up less effective.

There is also financial risk as the oil clean-up process must be undertaken in conjunction with the ship salvage.

"If we rushed out there independently that would be at the risk of it not being in the salvor's pocket."

The present capacity of the on-water recovery team is to be able to collect 40 tonnes of oil in a day.

On Sunday the capacity will have increased to a daily recovery maximum of 540 tonnes and by Monday night the responders' daily capacity will be far greater than the 1700 tonnes of fuel that is onboard Rena.

There is a storm due on Tuesday and if the sea swell is too high or too sharp, any on-water recovery operation is stalled.

The storm also presents a danger as it may damage the ship further and the leaking would resume – potentially at a faster rate.