It was founded in 1971 and managing director Doug Ducker joined the firm in 1974 as a process engineer.
"It has seen many changes as forest resources, product demands, process requirements and company ownership changed," Mr Ducker said.
The company had grown to operate on a global scale which he described as tremendous for the region.
"The 1.2 million tonnes of log we use yields around $115 million at wharf gate for export. By processing here at Whirinaki we secure employment for over 400 New Zealanders and increase gross revenues by over 140 per cent." More than 450 people are also employed by Pan Pac forestry contractors. It has 34,000ha and also buys logs.
The Pan Pac opening was an appropriate context for Economic Development Minister Steven Joyce's announcement of a regional investment attraction programme, to encourage more overseas investment in local economies.
New Zealand Trade and Enterprise will work with regions to create comprehensive investment profiles.
"The profiles will allow regions to clearly lay out the advantages they offer investors in terms of natural resources, infrastructure, the availability of skilled workers, and innovation hubs that support investment," he said.
"The regions that are doing the best are those that have a clear positive approach that welcomes investment and new opportunities."
To assist the programme, Regional Growth Studies have been commissioned, with the Hawke's Bay/Gisborne study the first to be released, due this month.
"The latest data shows that it is the regions that have been clearly leading New Zealand's recovery out of the global financial crisis."
Hawke's Bay Chamber of Commerce president Brent Linn said he looked forward to the initiative's details being released.
"It is fantastic for the region," he said.
Oji Holdings chairman Kasuhisa Shinoda said the success of Pan Pac's higher-grade pulp on overseas markets justified the investment and the company would like to expand further in New Zealand.
The two countries had "a wonderful relationship" and a shared love of sport. Mr Shinoda watched Japan play Canada at McLean Park in 2011 as part of the Rugby World Cup.
Mr Ducker reminded Mr Shinoda onstage that he had lost a wager over the Black Sticks women versus Japan hockey game on Thursday. New Zealand won 6-2.
Mr Joyce said Pan Pac "truly has a great association with the Hawke's Bay community".
The Government was looking to maximise opportunities for trade with Japan around sport, with Japan hosting the 2019 Rugby World Cup and the 2020 Olympic Games, he said.