Tottenham Hotspur have had a €14m (£10.7m) offer rejected by Alkmaar for the striker Vincent Janssen, with the Dutch club holding out for €20m.

Mauricio Pochettino is keen to add to his limited options up front and the Tottenham manager made a personal check on Janssen at the end of last month, when he watched him play for Holland against the Republic of Ireland in Dublin.

The 22-year-old has enjoyed a breakthrough season, finishing as the Dutch league’s top scorer and forcing his way into the Holland squad. He was developed as a youth player by Feyenoord but they did not offer him a contract and AZ signed him for €400,000 from Almere City. He has three years to run on his current deal.

It is understood that Tottenham proposed to spread the transfer-fee payments over a three-year period, which Alkmaar were not happy about. The club’s technical director, Max Huiberts, said: “The difference between the offer and the asking price is too big. I hear a lot of rumours but nobody else has made an offer.”

Pochettino wants to add depth and quality to his squad, ahead of their qualification for the Champions League group phase and he has already completed an £11m deal for the midfielder, Victor Wanyama, from his previous club Southampton.