The Belgian international has been in great form so far this season, bagging four goals and an assist in his last two games.
The 25-year-old emerged as a January transfer target for Liverpool, but it now seems Andre Villas-Boas is ready to rival Brendan Rodgers for the signature of the highly-rated winger.
Mertens can operate on either flank, and having joined PSV in June 2011, has gone to score 25 goals in just 38 appearances.
According to thisislondon.co.uk, Andre Villas-Boas wants another wide-player to challenge Aaron Lennon and Gareth Bale for starting spots, and the Spurs boss is also reportedly considering Crystal Palace star Wilfried Zaha and Shakhtar Donestk playmaker Willian.
But reports suggest Mertens would be available for just €13m, making him an attractive target for both Liverpool and Spurs.
A move to Tottenham could be facilitated by fellow Belgian Jan Vertonghen. The defender moved to White Hart Lane from Eredivisie side Ajax in the summer, and recently declared how happy he is with life at Tottenham.
But Liverpool boss Brendan Rodgers is still thought to be keen on the wide-player, who would offer competition for Raheem Sterling and Fabio Borini. England international Stewart Downing looks to have fallen out of favour at Anfield, so an opportunity could open up for Liverpool to sign another winger in Janaury.