Hales was fined and suspended for his involvement in a nightclub altercation with team mate Ben Stokes in 2017.
The 30-year-old was given a six-match one-day international ban in December. He had already missed two games and the remainder of the ban was suspended for 12 months so he could be available for selection.
The Professional Cricketers' Association (PCA) said it would not comment "on any individuals in relation to the recreational drugs policy" due to the organisation's duty of confidentiality.
The England and Wales Cricket Board (ECB) could not immediately be reached for comment.
The 50-over World Cup begins on May 30 with England taking on South Africa in the opening match in London.
(Reporting by Rohith Nair in Bengaluru, editing by Ed Osmond)
