The PSV winger is on the verge of becoming the Partenopei's first summer signing after passing a medical on Saturday
Club president Aurelio De Laurentiis has set out to reinforce new coach Rafael Benitez's squad in order to challenge for honours next term.
And it now appears a formality that Mertens will become the club's first summer signing after the 26-year-old passed his medical examination with the Partenopei.
"Dries Mertens underwent medical tests for Napoli this [Saturday] morning. The Belgian winger landed at Capodichino airport and then was taken to Cerreto Sannita medical centre (Benevento)," a statement on the club's website read.
"The tests were passed and were carried out by Napoli medical staff."
Mertens is anticipated to put pen to paper on a five-year deal with his new club, with Napoli reportedly stumping up €9.5 million for the winger.
The Belgium international scored 16 goals and assisted another 17 in 29 Eredivisie games this season.