Jakarta and some neighbouring provinces on Java island hit by a major electricity outage.

Indonesia's state power company PLN estimated on Sunday it would take several hours to restore power to Jakarta after a major blackout, blaming technical issues for cutting power to tens of millions of people in the capital and surrounding provinces.

The power outage spread across areas that are home to more than 100 million people and appeared to have affected most areas of the capital, prompting the use of generators in some offices, malls and apartments.

"Hopefully for the Jakarta system, if everything goes to plan and the generating system is reliable, smooth supply should return in approximately three hours," Sripeni Intan Cahyani, acting chief executive of PT Perusahaan Listrik Negara (PLN), told a news conference.

Cahyani said electricity customers in the provinces of West Java and Banten should get power back within four to five hours.

She blamed faulty transmission circuits at the Ungaran power plant in Central Java for causing voltage drops that hit power networks in Jakarta as well as West Java and Banten provinces.

"We will investigate to find the root causes and analyse them in detail. We will appoint an independent party to investigate," said Cahyani, who only took up her post on Friday.

Another PLN official said two out of three circuits had gone down triggering "cascading voltage" that caused outages as the west system collapsed.

Earlier on Sunday, the mass rapid transit (MRT) system in Jakarta had to evacuate passengers from trains after the power outage that began just before noon local time (0500 GMT).

The city of Jakarta is the centre for government and business in Indonesia and is home to more than 10 million people, with around three times that many people living in the surrounding towns. The capital does suffer periodic blackouts, but usually short-lived and confined to certain areas.

AIRPORT, HOSPITALS OPERATING NORMALLY

Operations at Jakarta's international airport remained normal using back-up generators, its operator said via Twitter.

Jakarta Governor Anies Baswedan also said via Twitter that public hospitals were operating as usual, relying on generators.

But at train stations, hundreds of passengers were left stranded after commuter lines stopped working.

"The train stopped all of sudden, we had to wait for a long time," said Ella Wasila, a passenger near Sudirman station in downtown Jakarta. "There were so many babies in the coach, they were crying, and people were shouting 'open the door'."

The power outage also disrupted some cellular phone networks and provider Telkomsel said it was compiling an inventory of the number of devices affected by the power cut.

The blackout also caused traffic lights to go out in some areas of the capital, creating traffic jams.

Wiwik Widayanti, chief executive of the Jakarta regional train service, said more than 800,000 people used the network per day at a weekend, so buses would be used to transport stranded passengers.

Indonesian Consumers Foundation (YLKI) said the blackout could discourage investment in Southeast Asia's biggest economy and urged the government to increase PLN's capacity.

"Power outages, especially in the Greater Jakarta area, are not only detrimental for residential consumers but also to the business sector," Tulus Abadi, an executive at the foundation, said in a statement.

Ordinary Indonesians also took to Twitter to express their frustration.

A Twitter user with the handle @henrydjunaedi said in a post: "I'm a cashless guy, this is nightmare ... So far I can only find one working ATM in a 10 km radius. Restaurants and markets are closing or not accepting card payments."