The South African fine paper producer has entered into a 90-day consultation period over the future of the Hemel Hempstead mill (pictured), which could lead to a relocation of production or its sale.
Nash produces 30,000 tonnes per year of uncoated business papers, including the Croxley Heritage and Supreme, Vanguard, Paradis and Silken brands.
Sappi Fine Paper Europe chief executive Wolfgang Pfarl previously announced an initiative entitled Everest to reduce costs and increase sales in Europe.
Sappi said it was finding it increasingly difficult in the UK, due to escalating costs making the mill uncompetitive.
Nash Mill's warehousing and sales facilities are not included in the talks.
The mill has a history that dates back to the 1700s, and was purchased by Sappi in 1990.