The North London club made an offer for the Italian midfielder earlier this week, but Newcastle quickly turned it down.
There are differing reports over the value of the bid. Sky Sports reporter Keith Downie said the proposal was worth around £80 million, while Daily Mail journalist Craig Hope reported a figure closer to £75 million.
Despite the setback, negotiations are not expected to end there. Discussions between the two clubs are set to continue as Tottenham remain keen on securing the midfielder.
Spurs are looking to make a significant addition to their squad following two disappointing Premier League campaigns, with Tonali emerging as a key target.
