The Magpies want £10 million for the defender this summer.
The Hornets are said to be looking into the signature of the player so that new manager Walter Mazzarri can utilise the wing-back system he is so famous for effectively next term.
However, he will not come cheap.
Leicester City's Jamie Vardy in action with Newcastle United's Daryl Janmaat
The Mail report that Newcastle have informed Watford of a £10 million asking price for the player should they wish to take him to Vicarage Road this summer.
Watford would therefore need to break the bank slightly if they were to get hold of the player, who is more than capable of playing in a wing-back role.
Daryl Janmaat celebrates scoring the fifth goal for Newcastle
Janmaat, who has 27 caps for the Dutch national team, cost the Toon an undisclosed fee in July 2014 after an impressive performance at the World Cup for the Dutch.
However, despite his obvious glimpses of ability, his defensive nous has been called into question on many occasions at St James Park.
Watford manager Walter Mazzarri before the game
Watford are looking to shape their team around Mazzarri’s system – which is perhaps best known from his time at Napoli.