The union has said that if the proposed closure goes ahead, a devastating blow will be dealt to the local economy.
Yesterday, trade union representatives and IP's mill management met with first minister and local MSP Alex Salmond.
All will now work together in the consultation process to secure the "best possible outcome" for the employees and the site, according to IP's spokesman.
He also said that normal production is set to continue at the mill well into the next year.
However, Unite assistant general secretary Tony Burke has that this is another "body-blow" to the papermaking industry in Scotland and to manufacturing throughout the UK.
He said his first concern is for Unite's members and their families at the mill.
"The position in the paper and packaging industries is becoming critical as we currently have over 1,000 members that are in consultation over closure or potential redundancy," he said.
However, reports have said that whatever the future of the site is, IP would not be involved.
IP announced on 22 October that it has entered into consultation with staff at its Inverurie mill.
The Aberdeenshire-based plant is the global paper and packaging company's only non-integrated fine paper mill, and it produces 250,000 tonnes of uncoated freesheet paper annually.
The move is a further blow for the Scottish paper industry following the closure of Curtis Fine Papers earlier in the year.
If the IP mill closes, it would mean that International Paper will exit the UK paper manufacturing sector.
Unite and Scottish government fight for staff at IP's Inverurie mill
Unite has hit out over International Paper's (IP) announcement that it may close its 371-staff Inverurie mill, as the Scottish government also pledges its support.