The country's supply chain is expected to be significantly impacted by Cyclone Gabrielle, which has added further pressure.

Commerce and Consumer Affairs Minister Duncan Webb says he has spoken to supermarket executives on Tuesday about the potential problems ahead.

He says products that are likely to be affected include salad packs, broccoli and bananas. He's been told a banana boat had been turned back in the cyclone.

Other items, such as bottled water and baked goods, are in short supply.

'The supermarket chains say their concern is getting roads open and getting power back on.”

Transporting New Zealand chief executive Nick Leggett says the supply chain is 'clearly going to be heavily impacted”.

'This is on top of existing issues with short supply of some goods, from recent weather and more general Covid pressures,” says Leggett.

The most resilient piece of the supply chain is trucking, and naturally the sector is restricted by road closures and by businesses and ports being closed to dispatch and receive goods, he says.

'However, if trucks can run, they will do so. Despite complete shutdown of rail and ports in some areas of the country, trucks will be on the road taking critical food and supplies and keeping the economy moving.”

Strong winds rolled a truck over on the motorway on State Highway 3 north of New Plymouth on Tuesday morning. Photo: Vanessa Laurie/Stuff.

Most trucks were out on the road on Tuesday morning, but high winds caused a Mainfreight truck to topple over on State Highway 3 in New Plymouth.

Truckies attempting to get essential supplies into Hawke's Bay ended up marooned on the roofs of their trucks after they were surrounded by water that rose to cab level.

Another truck in the Hawke's Bay had been hit by a falling tree, but the driver was uninjured.

'It's been quite hairy out there for drivers, and we have been encouraging operators to allow their drivers to make individual calls, so while they are making every effort to get supplies through, they are not putting themselves in danger.”

Some trucks that managed to get through to the Coromandel on Monday were unable to get out.

'While some places like the Coromandel Peninsula are cut off today, we expect contractors will get at least single lanes open relatively quickly, and most places have alternate routes. We expect areas, such as Bay of Plenty and Waikato, to start opening from tomorrow.”

Foodstuffs North Island chief executive Chris Quin says with difficult road conditions and closures throughout the North Island on Monday night and Tuesday, its drivers and suppliers are still attempting to safely get deliveries to the distribution centres and stores.

'While there has been some disruption to deliveries, all the preparation we've done in advance means we have plenty of essentials already at store.”

Quin encourages customers to continue to buy only what they need. From time-to-time customers may see temporary product limits for items that are in high demand.

Retail NZ chief executive Greg Harford says he understands there's still plenty of stock available, and retailers will be looking at their distribution networks to make sure they can keep supplying stores.

'Often, if there are gaps on shelves, it is because they haven't been refilled, so we're asking customers to shop normally, and if they are looking for something that's not on the shelf, it's a good idea to check with a team member.”

Northport, the first port to be hit by Cyclone Gabrielle, is looking at reopening on Wednesday if conditions permit, with the next ship due in at 2am.

The port's wave rider buoys, used to measure sea conditions, were blown ashore and will be reinstated once it can be done safely.

Ports of Auckland expected to resume full operations on Wednesday at 7am after closing on Sunday afternoon, and asking cargo ships to move to anchor or go out to sea.

A spokeswoman says it's too early to gauge the cyclone's impact on wider supply chains with road, rail and distribution centres also disrupted, but it's likely to take several weeks to get back to where the port was prior to the storm.

Congestion at the container yard was expected, and efforts to recover the 60 hours lost time would be limited to an extent by operational restrictions due to high winds and heavy weather.

'Once the cyclone has moved through, we will discuss the timing of restoring berth windows with the other ports.”

Tauranga resumed crane operations early Tuesday morning after the wind dropped, having suspended work at midday on Sunday, leaving about eight vessels riding out the storm at sea.

The Port of Lyttelton closed container and cruise berth operations at midday on Tuesday, and hoped to return to normal operations by Thursday at the latest. The Coral Princess cruise ship cancelled a visit, but two further cruises were due later in the week, including the giant Ovation of the Seas.

Wellington's CentrePort said the closure of Picton Harbour to all vessels had led to the cancellation of Cook Strait ferries, and if winds became excessive, high risk areas of the container terminal would close.

- Brianna Mcilraith and Amanda Cropp/Stuff.