* Opponent says Chavez should show himself
* President's signature appears in decree
* Unseen in public since Dec. 11 surgery
By Andrew Cawthorne
CARACAS, Jan 16 (Reuters) - Venezuela's opposition leader, Henrique Capriles, called on Wednesday for a proof of life from ailing President Hugo Chavez, who has not been seen publicly since cancer surgery in Cuba five weeks ago.
Chavez's signature appeared in the government's official gazette on Wednesday in a decree naming his new foreign minister - though the document wrongly placed him in Caracas.
"If the president of the republic can sign decrees, I call on him to show himself, to talk to Venezuela," Capriles said at his inauguration for a new term as Miranda state governor.
"He should tell us everything that's happening in government because what we have in Venezuela is misgovernment."
Officials say Chavez, 58, is improving despite his grave situation after a fourth operation on Dec. 11 for a cancer first detected in the pelvic area in mid-2011.
Many Venezuelans suspect, however, that he could be dying or unable to return to active rule after 14 years at the helm of the South American OPEC member of 29 million people.
Stirring the national guessing-game over Chavez's condition, the appearance of his signature had Venezuelans wondering whether the president had signed the decree from his hospital room, or even if officials might have scanned an old one.
Allies insist Chavez remains in charge and is giving instructions from Cuba, though that infuriates the opposition who fume that Venezuela's capital has become Havana.
Should Chavez step down or die, triggering an election, Capriles, 40, is likely to stand again for president after defeat in October last year. He would face a stiff fight against Chavez's chosen successor, Vice President Nicolas Maduro.
Maduro, a 50-year-old Chavez protege who rose from bus driver to the nation's No. 2, has taken on day-to-day leadership in Venezuela, while the president's condition is unclear.
That has infuriated opposition leaders, who say Chavez's non-appearance at the scheduled Jan. 10 inauguration of a new presidential te rm me ans he should be formally declared absent, leading to the appointment of a caretaker leader and a vote.
Fellow Latin American nations have generally accepted the Venezuelan government's position, though Brazil this week pointedly called for quick elections if Chavez leaves power.
And a representative of Panama's right-wing government lashed Venezuela at a meeting of the Organization of American States (OAS) on Wednesday, its envoy, Guillermo Cochez, quoting one opinion that "what we are seeing is a sick democracy."
That unleashed a torrent of criticism from Caracas, with its ambassador to the OAS and state media accusing the Panamanian diplomat of being in league with "fascists" and "conspirators" within Venezuelan opposition circles.
The Panamanian government later issued a statement rebuking Cochez for "improvised" comments that were not an official position. "Panama will continue to respect states' internal political processes, and in the case of Venezuela, we pray for the quick recovery of President Hugo Chavez's health," it added.