By Andrew Cawthorne and Diego Ore
CARACAS (Reuters) - Venezuela's opposition must define within weeks its strategy for ending Nicolas Maduro's presidency given the OPEC nation's "monstrous" economic crisis, opposition leader Henrique Capriles believes.
Having won control of the National Assembly last month due to voter ire at Venezuela's punishing recession, the opposition coalition has vowed to find a constitutional mechanism to oust Hugo Chavez' successor in the first half of 2016.
Options for the multi-faction coalition include demanding his resignation, forcing a recall referendum as allowed half-way through his term, or reforming the constitution to trigger a new presidential election.
"We have to find a common position. The clock is ticking ... We can't wait longer than the first quarter," Capriles, a state governor who narrowly lost a 2013 presidential vote to Maduro, told Reuters in an interview late on Thursday.
"We still haven't seen the full monstrousness of the crisis ... Venezuela is heading toward a denouement this year," added Capriles, likely to be a contender in any scenario of a new new presidential election.
OPEC member Venezuela is suffering the world's steepest inflation, a third year of economic contraction, and shortages of basic foods and medicines causing long lines nationwide.
Maduro blames an "economic war" by foes, plus the global oil price plunge, but critics say the mess is mainly the result of dysfunctional state controls over 17 years of socialist rule.
Capriles, 43, said it was impossible Maduro would step down voluntarily given his conviction he was the standard-bearer of "Chavismo" who must never surrender.
Seeking a recall referendum may be messy, he added, given Maduro-leaning judicial and electoral institutions could delay it into 2017, meaning his vice-president would take over rather than there being a new election if he lost the plebiscite.
So a constitutional reform might be the best way forward, Capriles said, explaining that would also enable the opposition to make changes like reducing the current six-year presidential term and prohibiting indefinite reelection.
Since the government's December defeat, Maduro, 53, a former bus driver and foreign minister, has taken a hard line, trying to reduce the new assembly's powers and vowing to veto intended laws such as an amnesty for jailed opponents.
"Any denouement has to be constitutional ... a military intervention would be the worst thing possible," said Capriles, who was jailed for four months in 2002 over a protest at the Cuban Embassy and now leads the opposition's more moderate wing.
(Editing by Alexandra Ulmer and W Simon)