British Prime Minister David Cameron has left Northern Ireland peace talks after making a conditional offer of extra money for the region's Catholic-Protestant government, but local leaders dismissed his pledge as bogus.

Friday's early exit by Cameron from the talks dashed hopes of reaching a wider agreement to sustain power-sharing, the central achievement of Northern Ireland's 1998 peace accord.

Cameron billed his overnight talks with rival Protestant and Catholic leaders as productive. He said he offered them an extra 1 billion pounds ($1.6 billion) on condition they resolved several other disputes undermining their five-party administration.

Sinn Fein leader Gerry Adams, whose nationalist party represents most Catholics, called Cameron's intervention irresponsible and amateurish. Protestant politicians blamed both Sinn Fein and Cameron for the impasse.