Venezuelan lawmakers voted on Tuesday to postpone the inauguration of ailing President Hugo Chavez for his new term, prompting complaints from opponents who called it a violation of the constitution.

Chavez's congressional allies, who hold a majority of seats in the National Assembly, agreed with a government proposal for Chavez to be sworn in at a later date before the Supreme Court. While pro-Chavez lawmakers approved the plan with a show of hands, opponents condemned the action as illegal.

Vice-President Nicolas Maduro broke the news that Chavez would not be able to attend Thursday's scheduled inauguration in a letter to National Assembly President Diosdado Cabello, confirming suspicions that Chavez's battle with cancer and a related respiratory infection would keep him in a Cuban hospital past the key date.

Maduro said that on the recommendation of Chavez's medical team, his recovery process "should be extended beyond Jan. 10."

The vice-president said Chavez was invoking a provision in the constitution allowing him to be sworn in before the Supreme Court at a "later date." The opposition disputed that argument and appealed to the Organization of American States, but did not appear to have other immediate routes to block the government's plan.

Tensions between the government and opposition have been building for days in the dispute over whether the ailing president's swearing-in can legally be postponed. The president underwent his fourth cancer-related surgery in Cuba last month and hasn't spoken publicly in a month.

'We aren't in Cuba'

Opposition leader Henrique Capriles said earlier Tuesday that Chavez's current term constitutionally ends Thursday and that the Supreme Court should rule in the matter.

Other opposition leaders have argued that the inauguration cannot legally be put off and that the National Assembly president should take over as interim president if Chavez hasn't returned from Cuba on inauguration day.

"The Supreme Court has to take a position on what the text of the constitution says," said Capriles, who lost to Chavez in presidential elections three months ago. "There is no monarchy here, and we aren't in Cuba."

However, Capriles said he saw no reason to bring a formal challenge to the Supreme Court because it was obliged to issue a ruling on the dispute.

The Supreme Court on Tuesday rejected a legal challenge brought by an individual lawyer, Otoniel Pautt Andrade, who had argued that it would violate the constitution for Cabello to refuse to assume the presidency provisionally if Chavez were unfit to be sworn in on the set date. The court's ruling didn't provide a detailed interpretation of the constitution, but it made clear the court backs the government's stance that Cabello need not assume the presidency at this stage.

Jan. 10 deadline for oath disputed

The Venezuelan Constitution says the presidential oath should be taken before lawmakers in the National Assembly on Jan. 10 but adds that the president may also take the oath before the Supreme Court if he's unable to be sworn in before the assembly. Government officials argue that clause does not explicitly mention a date, though opponents say it clearly refers to the Jan. 10 deadline.

While leaders of both pro- and anti-Chavez camps say they don't expect violence to break out Thursday, the dispute could give the opposition grounds to question the legitimacy of government officials serving past the scheduled inauguration date.

"Who's governing Venezuela? In Venezuela, Havana is governing, and that's the problem we have." —Opposition congressman Julio Borges

Maduro said in his letter that Chavez's condition was an "irrefutable unexpected reason" that made it impossible for Chavez to attend the scheduled inauguration.

Cabello announced during the legislative session that he had received the letter from Maduro.

The announcement set off an impassioned debate in the National Assembly. Opposition lawmaker Omar Barboza dismissed Maduro's proposal and urged Chavez's allies to accept Cabello as interim president while Chavez recovers, saying that was to avoid an "institutional crisis."

Barboza said it's clear that a "temporary absence" should now be declared, which would give the president 90 days to recover, and which could be renewed for another 90 days.

Some lawmakers called for a medical team to be formed to determine Chavez's state. Some also questioned why the letter was signed by the vice-president rather than Chavez himself.

"Who's governing Venezuela? In Venezuela, Havana is governing, and that's the problem we have," opposition congressman Julio Borges said during the debate.

Barboza said that if Chavez's allies continue with their stance, the opposition will be forced to "convoke the people of Venezuela to re-establish the validity of the constitution." He didn't elaborate.

As he announced lawmakers' approval, Cabello said: "President Chavez, this honourable assembly grants you all the time you need to tend to your illness."

Legal questions over inauguration

Legal experts have joined politicians in debating whether the inauguration can legally be postponed.

Constitutional law expert Henrique Sanchez Falcon, a professor at Central University of Venezuela, called the government's position "something that's absolutely contrary to what's established under the constitution, which says that the term lasts six years."

Maduro has called the swearing-in a "formality" and said the opposition is erroneously interpreting the constitution. Chavez has said that if he's unable to continue on as president, Maduro should take his place and run in an election to replace him.

Capriles noted, however, that Maduro "wasn't elected" to continue leading a government in Chavez's absence into a new term. "If Maduro wants to be president, it's not through that way," Capriles said.

He added Tuesday that he has spoken with members of the military, and that they have told him "we are with the constitution."