* Outages hit eight states on Tuesday night
* Caracas faces staggered cuts for maintenance, metro hit
* Colombia bomb causes failure of major power plant (Adds comment on electricity system, gas pipeline still down)
CARACAS, March 30 Widespread power failures hit Venezuela this week, leaving eight states including oil-producer Zulia without light for hours and causing chaos on the Caracas metro in a new headache for President Hugo Chavez.
Staggered blackouts will also be imposed on several areas of the capital for maintenance until Friday, the city's state-owned power company said in a statement. Experts predict irregular services will continue in the coming months.
Hours-long blackouts hit the eight states on Tuesday when the main power station in Zulia failed after a suspected rebel bomb on a Colombian gas pipeline that feeds it. [ID:nN28183779]
As a result, power was cut in three states to ration supplies, Vice President Elias Jaua said late in the evening.
"What happened tonight in Lara, Carabobo and Anzoategui, among others, was part of a rationing plan to balance the national system, which at the moment is facing high demand from states such as Zulia as a result of the outage at its main electricity plant," Jaua said in a phone call to state TV.
Four states in the OPEC member's Andean region were also left in the dark when a transmission cable failed late on Tuesday, state electricity company Corpolec said.
To cap it all, Caracas' main metro line collapsed during Tuesday's morning and evening rush-hours, causing panic as thousands of people were evacuated from packed trains after an electricity failure. Sporadic problems were reported with the metro on Wednesday.
Last year a long drought revealed severe weaknesses in Venezuela's electricity generating system, forcing power rationing for months.
Chavez declared a national emergency then and ordered billions of dollars of investments to install oil-fired plants aimed at reducing the country's dependence on hydropower.
But he canceled a plan to ration electricity in Caracas after a chaotic first day of cuts last year left poor, crime-ridden neighborhoods in the dark and workers stuck in elevators.
Miguel Lara, who formerly ran the coordinating body of the national grid, said the problems revealed by the drought were still present despite ample rainfall in recent months.
"The electricity crisis is still latent because there is stress on the system. The infrastructure is insufficient to meet the demand," he told Reuters. "We will continue to suffer unexpected service cuts."
The gas pipeline that exploded on Monday in Colombia is owned by Venezuela's state oil company PDVSA and operated by Chevron (CVX.N). It remained out of service on Wednesday.
"They are in the process of repairing the gas pipeline, and it is not yet transporting," said an official at Colombian state oil company Ecopetrol.
Lara said Zulia's Termozulia electricity plant, designed to run on oil as well as gas, should not have suffered an outage because of the damaged pipeline.
"It seems diesel was not available in the tanks," he said.
Venezuela's fuel consumption is growing rapidly, partly due to the government's strategy of building oil-fired power stations. Diesel consumption was up 27 percent in February, which means less export income for the state. (Additional reporting by Marianna Parraga in Caracas and Patrick Markey in Bogota; Editing by Daniel Wallis, Toni Reinhold)