The Eredivisie champions turned down an offer from Newcastle earlier this summer, and they have now decided to reward Anita with a new and improved deal.
"Ajax do not want to lose Vurnon. Therefore we have offered him a new deal until 2015 or 2016," sporting director Marc Overmars said to De Telegraaf.
"The coaches are very clear and see Vurnon as an important first team player. We don't want to let go of him. He will become one of the top earners at Ajax with his new contract."
The 23-year-old's current contract with Ajax is due to expire in the summer of 2014.
Anita, who has been capped at senior level for Netherlands, has made 108 Eredivisie appearances for Ajax since making his first team debut in 2005-06.
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