Senanayake, who has twice recorded career-best figures in the ongoing Royal London series against England, was reported by umpires Ian Gould and Marais Erasmus at the end of his team's victory at Lord's on Saturday.
He will be free to bowl again in the series decider at Edgbaston on Tuesday, but will face further scrutiny under International Cricket Council regulations.
An ICC press release read: "The umpires' report cited concerns over a number of deliveries that were considered to be suspect.
"Senanayake's bowling action will now be scrutinised further under the ICC process relating to bowlers reported in Tests, ODIs and T20Is.
"The off-spinner is required to undergo testing within 21 days, and, during this period, he is permitted to continue bowling in international cricket until the results of the testing are known."
- Sports & Recreation
- International Cricket Council