Gareth Southgate watched on as Maddison, 21, starred in Leicester's 2-0 win over Newcastle at St James' Park on Saturday.
Maguire remarked: "He's definitely good enough to play for England.
"If he keeps improving he'll get the call and he will take the challenge on."
Claude Puel also praised the midfielder, saying: "James Maddison continues to give his best and improve.
"We need to keep calm about him. He has started well but he needs to keep his head on his shoulders - keep consistent and continue to be clinical with us."