The company said the receipt of the $600m initial purchase price will strengthen its financial profile and will also reduce its $500m debt.
In addition to sale proceeds, there is an earn-out capped at AUD$100m based on the perfomance of the business over the next three years.
The company expects a 20-25% reduction in sales volumes in the second half of 2009 compared with the previous year.
It also said that full-year divisional EBIT reported before corporate and significant items is expected to be 30-35% lower than in 2008.
As a result of the divestment, Paperlinx has moved away from paper manufacturing and will now focus on its core paper merchanting business.
The company said current business conditions remain difficult with weak economic conditions impacting sales volumes in all markets.
The sale to Nippon Paper Group, which was first announced in February, excludes the two Tasmanian mills at Burnie and Wesley Vale.