The Evacuation Site has temporary shelters and a water supply for local residents but the path to it is blocked by hundreds of fallen trees. Mr Ducker said an alternative site would be made available until the forest was open again, around the end of June.
Native plantings would be protected from damage during the forest harvest and tracks returned to their original state.
A letter to Whirinaki Beach residents said harvesting was a hazardous activity and in the interests of health and safety the forest was closed 24 hours.
"Plans are in hand to arrange a meeting with Civil Defence to sort out an alternate Tsunami evacuation route/site," the letter said.
Mr Ducker said the forest suffered extensive damage because of a combination of unusual wind direction "straight off the sea" and water logged soil.
Apart from the Whirinaki forest overall damage to Pan Pac's estates totalled less than 10 ha, he said.
Cyclone's Cook's north-easterly winds hammered Hawke's Bay from 8pm on April 13, downing hundreds of mature trees in suburban areas throughout the region.
Fallen trees caused 15,000 customers to be without electricity in Hawke's Bay the following morning and it was three more days before supply was restored throughout the region.