CARACAS, Venezuela (Reuters) - Mediators were set to make a fresh bid on Thursday to break the political deadlock in Venezuela, where a strike aimed at forcing leftist President Hugo Chavez to quit has drastically cut oil shipments from the world's No. 5 exporter.

Anti-Chavez groups have called fresh street protests for Thursday in their campaign, now in its fourth week, which has rattled global oil markets and caused gasoline shortages at home.

"Wake up, Mr. Chavez, the country is dying in your hands. The strike continues, a fight until victory, not one step back," Carlos Ortega, an anti-government union boss, said on Wednesday.

Oil prices this week hit a two-year high driven by market jitters over the Venezuelan export shutdown and fears over a U.S. war in Iraq. Venezuela usually supplies more than 13 percent of U.S. oil imports.

Chavez, who was elected in 1998 and survived a coup in April, has dismissed opposition demands for an early vote. The former paratrooper, who led a botched coup himself 10 years ago, insists most people support his reforms to ease poverty and vows to defeat the strike.

His foes accuse Chavez of driving the economy into a sharp contraction and say his fiery populist rhetoric has fueled class hatred.

NEGOTIATIONS GOING NOWHERE

Negotiations between the government and opposition, brokered by the Organization of American States (OAS), have so far failed to reach an accord on an electoral solution.

"Unfortunately until now, the government has had a series of excuses for delaying an electoral solution," said Timoteo Zambrano, one of the opposition negotiators.

Talks were suspended over last weekend after government negotiators failed to show up. But OAS chief Cesar Gaviria was scheduled to resume talks on Thursday afternoon following a brief Christmas break.

The opposition, an alliance of political parties, social groups, unions and business leaders, is pressing for elections in the next three months.

But Chavez says the constitution only allows for a binding referendum on his rule in August -- halfway through his current term, which ends in February 2007.

With appeals against what he calls elite corruption, Chavez says his policies increase social justice in a nation where, despite huge oil wealth, the majority live in poverty. Still, opinion polls show that his popularity has slipped.

The strike has delivered a crippling blow to the government's oil industry and is costing more than $40 million a day. Oil provides more than half of government revenues.

Many analysts believe Chavez is now settled in for a long-haul battle. He still controls the government and appears to have the loyalty of top military commanders. He could also tap into about $15 billion in international reserves.

Chavez has sacked dozens of dissident managers at the state oil firm PDVSA and sent troops and pro-government loyalists to take over strike-bound tankers, refineries and port terminals.

But his counter measures have so far barely dented the strike. Vital oil exports were trickling out at 5 percent of November levels of 2.7 million barrels per day. Production had fallen to under 200,000 bpd compared with 3.1 million bpd last month.

By Patrick Markey