Shillingford has taken six wickets at 42.66 in the first two Tests against New Zealand but will now not be available for the final match in Hamilton which starts on Thursday. Samuels has not bowled in the current series.
An ICC statement said that an independent biomechanical analysis had revealed that for both Shillingford's standard off-break delivery and his doosra, the amount of elbow extension in his bowling action exceeded the 15 degrees' level of tolerance permitted under the ICC regulations. Shillingford will remain suspended until he submits a fresh analysis that proves his action has been corrected.
Ottis Gibson, the West Indies coach, said: "Though I felt confident about the way the two players performed at the testing, the report did not come back in our favour. Shane is obviously gutted, but Marlon's role in the team, as I have said previously, is primarily as a batsman, so the impact on him is a little bit less."
"We will formulate a suitable plan of action and work to rehabilitate their bowling actions in the New Year, so Shane can continue his international career in the shortest possible time and Marlon can continue to contribute with the ball when he's required.
"They are both tough characters and have had their share of ups and downs in the game over the years. We have no doubt that they will emerge from this latest setback with the utmost confidence."
Earlier this week, when asked about the pending report, Gibson hoped that Shillingford would not be singled out. "There are a few people around the world bowling with similar, if not worse actions, so I expect him to be cleared for sure."
Meanwhile, the analysis on Samuels' action revealed that the spinner's standard off-break delivery was legal but the quicker delivery exceeded the prescribed levels of tolerance.
If Samuels is reported for a suspect action in the next two years, the ICC will take note of it as a second report and the player will have to undergo a biomechanical analysis. If the analysis concludes that Samuels has an illegal action for any delivery, he will be banned from bowling in international cricket for a minimum period 12 months.