Bangladesh's Shakib Al Hasan banned from bowling in ECB competitions
Shakib was reported by umpires during the spinner's one-game appearance in the County Championship for Surrey in September.
The 37-year-old left-armer was signed specifically for the crucial clash with title rivals Somerset on a Taunton pitch that was expected to help spin bowling.
Shakib took nine wickets across both innings' in Surrey's 111-run defeat, with his team going on to win the title despite that loss.
An ECB statement read: "Bangladesh all-rounder Shakib Al Hasan has been suspended from bowling in ECB competitions following an independent assessment of his bowling action.
"Shakib's action was reported by the standing umpires while he was playing for Surrey in the County Championship match against Somerset in September.
"Shakib completed an independent assessment at Loughborough University earlier this month, which found that the elbow extension in his bowling action exceeded the 15 degree threshold as defined in the regulations.
"This suspension takes effect from the receipt of the independent assessment on 10 December 2024."
Shakib, who has not signed a contract with an English county for the 2025 season, is ineligible to bowl in ECB competitions until he has passed an independent re-assessment of his bowling action.
He has played 71 Tests, 247 one-day internationals and 129 Twenty20s for Bangladesh, taking a combined 712 wickets.