Since departing Chelsea in January last year, the centre-back has established himself as one of the best defenders in Serie A, making a total of 48 appearances.
The 24-year-old made his 30th start of the 2021-22 campaign on Sunday as Milan defeated Sassuolo to end their 11-year wait for another top-flight crown.
According to The Telegraph, Milan are prepared to reward Tomori by offering him a new deal, despite his current terms not due to expire until 2025.
The Italian giants allegedly want to ensure that the England international remains at San Siro in the long term, acknowledging that they pulled off a coup by signing the player for just £25m.
Having settled in Italy, Tomori is expected to accept the updated proposal at a time when he is said to be targeting a recall to the England squad ahead of the World Cup.