The duo have been made unavailable after key all-rounder Stokes was arrested in Bristol in the early hours of Monday morning following England's 124-run win in the third ODI in the southwest city on Sunday.
Hales was with Stokes on Sunday night.
"Ben Stokes and Alex Hales will not be available for tomorrow's one-day International match against West Indies at The Oval," ECB director of England cricket Andrew Strauss said while reading out a board statement to reporters at The Oval on Tuesday.
"Stokes was arrested in the early hours of Monday morning, 25 September, following an incident in Bristol," the former England captain added as he continued to read out the statement.
"He was held overnight and released under investigation — without charge — late on Monday and will not join the team in London.
"Hales, who was with Stokes on Sunday night, did not train this (Tuesday) morning and has returned voluntarily to Bristol today to help police with their enquiries.
"You will understand that we cannot offer further detail at this stage but will provide any updates when we can."
England are due to name their squad for the Ashes Test series in Australia on Wednesday.
Strauss confirmed that both Durham star Stokes — a Test regular — and Nottinghamshire batsman Hales, a fringe candidate, will be considered for the Ashes squad on cricketing grounds alone by the England selectors at this stage.
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