Major Bay of Plenty employer Whakatane Mill has decided to proceed to close its doors.

It employs just over 210 staff and has produced paper and packaging products, lately mostly for export, for more than 80 years.

Its management says all staff would be made redundant, with most completing their roles by the end of June.

The company would cease production on June 21 and then begin the decommissioning of the plant, with an expected final closure date of June 30, it says.

A number of options are being explored for both the plant and the site, but no decisions had yet been made.

Whakatane Mill Limited general manager Juha Verajankorva says the decision is not an easy one.

"This is a very tough day for all of us, and we will work to do the best we can by our people and the community of Whakatane and the Bay of Plenty as we complete our decommissioning and closure of the plant," he says.

"Our focus at this time is caring for our staff and we will continue to work with union representatives and other agencies to support our people through the redundancy process."

The mill proposed the closure last month after losing its biggest customer, Swiss packaging company SIG Combibloc, which accounts for 80 per cent of its sales.

"It's very tough, but SIG's decision is understandable, given the circumstances and the reality that we cannot compete with suppliers elsewhere. We accept that further investment in the business is just not feasible," he says.

The business is no longer considered economic.

"The volumes we produce are modest by global standards, and our costs-per-unit can no longer compete."

The EMA says the announcement the Whakatane Mill is closing is terrible news for the management team, employees, and the wider community.

"Our thoughts are with everyone in Whakatane today, as this is a decision that everyone was hoping would not be necessary," says Chief Executive Brett O'Riley.

"It's such a shame that no viable option emerged from its consultation process, and that without a buyer the only option has been for the mill to close."

The company will cease production on June 21 with 210 employees being made redundant, followed by the decommissioning of the plant and expected final closure on June 30, 2021.

O'Riley says the EMA supports member businesses throughout the Bay of Plenty and hopes that through its involvement with the successful Rotorua-based ReTrain programme it may be able to help.

"It's very sad to see a business that has been producing paper and packaging products for more than 80 years close because the competitiveness of its products has been eroded," he says.

"If we can do anything at all to help, we will."

-Additional reporting by RNZ