"The match officials' report, which was handed over to the Sri Lanka management, cited concerns about the legality of the 22-year-old's bowling action," an ICC media release stated.
Kaushal had a reasonably good series against India with 13 wickets from three Test matches including eight wickets in the home team's victory at Galle.
"Kaushal's bowling action will now be scrutinised further under the ICC process relating to suspected illegal bowling actions reported in Tests, ODIs and T20Is. He is required to undergo testing within 14 days, and, during this period, Kaushal is permitted to continue bowling in international cricket until the results of the testing are known," the release stated.