The incident happened in the 50th and final over of England's innings in their World Cup clash when Lakmal bowled a second consecutive high, full pitched ball to Buttler, after being given a first and final warning by on-field umpire Rod Tucker earlier during the same over
Lakmal was stopped from bowling at Wellington's Westpace Stadium and reported to the match referee David Boon for dangerous and unfair bowling.
"While making my decision, I took into account that it is was dangerous and unfair bowling, there were no mitigating circumstances, and there was no remorse from the bowler," said former Australia batsman Boon.
Sri Lanka won the match by nine wickets, although Lakmal ended with expensive figures of one for 71 from 7.4 overs.