Mr Wong said he was quitting the business to retire and Foodstuffs had bought the business and the building.
"Eventually they are going to build a brand new New World on this site," he said.
His daughter helped him re-label fresh produce on Sunday morning, ahead of Write Stuff's final afternoon's trade.
Unsold stock would be sold to New World or Foodstuffs.
Long-term customer Mike Whitworth said he was surprised to find out both Wairoa supermarkets were part of the same chain - there is a nearby New World.
"It is only a little town and it is great to have some competition," he said.
Prices were competitive, so he said it was not worth the cost of driving to Gisborne or Napier to shop.
The closure would be a boon for the remaining New World, which has taken on staff from Write Price, until Foodstuffs rebuilt.
"What the outcome is, God only knows."
Mr Wong said he would likely move to Napier next year to be nearer his daughter and grandchildren.
"I'll spend more time with the family and maybe do a trip here and there."
He said he wished to thank all Write Price customers and staff "who have been more than wonderful".
A Foodstuffs spokeswoman would not say when the new New World would be built.
"We are continuing to work on our development plans for New World Wairoa and we will communicate more detail as soon as we have firm timelines."