Leading goalscorer Remy has a calf complaint that is likely to keep him out until the end of the month, while full-back Debuchy is expected to miss the next four fixtures with a groin injury.
The news was confirmed by the club on Thursday and comes as a further blow to Newcastle, who already have manager Alan Pardew banned for seven matches following his headbutt on Hull City's David Meyler.
The St James' Park outfit could now be without the duo for matches against Fulham, Crystal Palace and Everton.
Remy currently tops the Newcastle scoring charts with 13 goals in 23 Premier League appearances.
Newcastle head into this weekend's clash at Craven Cottage with a view to closing in on a potential UEFA Europa League qualifying berth.
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