According to Sky Italia and journalist Gianluca Di Marzio, a move for the midfielder to Spurs is edging closer.
The north London club are reportedly offering Newcastle United a fee of €100million for Tonali.
Tottenham are now waiting for a final answer from the Magpies, who signed the 26-year-old from AC Milan for just over €60million in the summer of 2023.
The interest in Tonali comes only a day after it emerged that Spurs had agreed a deal worth around €98million with West Ham United for midfielder Mateus Fernandes, 21.
Should Tottenham also complete the signing of Tonali, the club would have added two central midfielders for a combined fee of around €200million.
Tonali has established himself as one of Newcastle's most important midfielders since his move to St James' Park, helping the club win the EFL Cup in 2025, their first major domestic trophy in 70 years.
The Italy international featured 53 times for Newcastle last season, scoring three goals and providing seven assists across all competitions.
His potential departure would represent a significant blow for Newcastle United, who have built their midfield around the Italian since his arrival from Italy.
Fernandes, meanwhile, arrives at Tottenham as one of the club's marquee signings of the summer, with the fee reported as a club record for the north London side.
The scale of the spending underlines Tottenham's ambition this summer as they look to build a squad capable of competing on multiple fronts following their recent European success.
Newcastle's response to Tottenham's offer for Tonali is expected in the coming days, with the north London club hopeful of wrapping up a deal before the transfer window progresses much further.