The 29-year-old's current terms are due to expire at the end of next season, but his representatives are understood to be negotiating a renewal with Tottenham.
Despite coming under criticism for some underwhelming performances this term, Dier retained the trust of Antonio Conte and is also a regular fixture in the first XI for Cristian Stellini.
The centre-back's early-season form also saw him force his way back into the England squad for the 2022 World Cup, making two substitute appearances for the Three Lions in Qatar.
While Dier is currently focused on the final few weeks of the campaign, contract talks between the club and his entourage are said to be progressing positively in the background.
According to Football Insider, all parties are now expecting a renewal to be finalised with minimal fuss, and Dier is poised to sign a new deal until the summer of 2026.
The report adds that Spurs will pull out all the stops to keep Dier regardless of their managerial situation, as multiple coaches have placed their faith in the Englishman.
Dier is thought to be earning approximately £85,000 a week under his current terms, which he penned in 2020, but it is unclear whether he will enjoy any sort of pay rise with his new deal.
The former Sporting Lisbon and Everton youngster signed for Spurs in a £4.5m deal in 2014, and he made his first-team breakthrough as a midfielder before transitioning to a defensive role.
Dier has posted a total of 13 goals and 12 assists in 357 matches for Tottenham in all competitions over the past nine years, scoring twice and setting up one more in 38 matches this season.
The England international completed the full 90 minutes in Saturday's dramatic 3-2 loss to Bournemouth, which keeps Tottenham fifth in the Premier League standings, three points behind Manchester United having played two games more.
Despite Dier's imminent extension, Spurs will be expected to enter the market for a new centre-back this summer, and it has been reported that talks are underway with Barcelona over a permanent move for Clement Lenglet.
Aymeric Laporte, Kim Min-jae and Marc Guehi have also been mooted as possible signings, while Spurs and North London rivals Arsenal are thought to be tracking Swansea City's Nathan Wood.
A first-half injury to Lenglet saw Davinson Sanchez introduced against Bournemouth, but the Colombian endured a dreadful afternoon and was booed by his own supporters before coming off.
Club captain Hugo Lloris admitted that Tottenham fans turning on their own player was unlike anything he had seen in his career, and with Sanchez's contract expiring in 2024, the 26-year-old could be on the move this summer as well.