Earlier this week Hawke's Bay experienced extreme wind conditions of up to 45 knots (85km/h), and two empty containers were flung off a stack in the container terminal and into the water early Tuesday morning.
The first container was discovered on the beach between Westshore and Bay View along with a large navigation buoy which broke its moorings in extreme swells.
The Napier Port used a tug and pilot boat to actively search for the second container, which they believed punctured and sunk when it was blown from the terminal.
"At 45 knots, the wind gusts hitting Napier Port have been extreme and as far as we can recall, we have never had a container blown into the water like this before," Dawson said.
Harbourmaster Martin Moore said the region experienced large swells, the highest reaching 8.5m.
"It is not unusual for the waves to be breaking along marine parade up onto where the cycleway is.
"Nor is it unusual for the waves to be breaking over the top of the breakwater wall and on to the tops of the fertiliser sheds there. Winter storms are not pleasant, you wish they didn't happen, but they do," he said.
Dawson said the massive swells of over 8m were the largest recorded in Hawke's Bay so far.
"The 8.5 metre swell recorded earlier this week is high for a winter storm, in fact it's the highest reading that Napier Port has seen in recent history."