In a statement, team spokesman Andy Walpole said the breach had taken place here on Friday night following England's six-wicket defeat by New Zealand in their opening Group C World Cup match earlier in the day at the Beausejour Cricket Ground.
The breach was reported to the England team management at breakfast time on Saturday and the decision to fine the players involved taken at a subsequent team meeting, attended by the whole squad and management, at noon local time.
Walpole, who refused to name the players involved, the extent of their fines, or the exact nature of the breach, said in a statement: "The England team management today (Saturday) announced that a number of England players had been fined by the head coach, Duncan Fletcher, after admitting to a breach of team discipline last (Friday) night.
"The decision followed a team meeting at noon today (Saturday) which was attended by all the players and management."
England's next Group C match is against Canada on Sunday.