TAIPEI - Taiwan will conduct a comprehensive review of its weak electrical grid, a day after the island suffered its worst blackout in nearly two decades, which the government-owned oil company blamed on a flawed power supply replacement process.

In brief remarks to reporters on Wednesday (Aug 16), President Tsai Ing-wen said the widespread power outage across 17 cities and counties showed the island's electrical grid was "fragile" and it will be her administration's top priority to re-examine and strengthen the island's infrastructure.

She said she has ordered a review team to be set up to look into possible errors or flaws in the work processes within power stations, and ways to better stabilise the island's electrical supply.

The president added that if the government does not deal with the problems correctly, Taiwan will face a "high risk in its systems".

Ms Tsai, whose approval rating recently hit a record low of 29.8 per cent, apologised on her Facebook page on Tuesday night. She wrote: "Electricity is not just a problem about people's livelihoods but also a national security issue. A comprehensive review must be carried out to find out how the electric power system can be so easily paralysed by human error."

Noting that Tuesday's power failure should not be seen as an "isolated case", Premier Lin Chuan said the review team must identify and rectify management gaps in Taiwan's power companies.

He said in a news briefing on Wednesday that the review team will rope in international experts to put in place additional precautions and safeguards to stabilise the electrical grid and prevent future massive power outages.

Mr Lin also floated the possibility of more pipelines from which electricity is being supplied from the power plants to users such as households, offices and industrial areas.

"From the incident, we can see that the foundation facilities are weak and we need to have more and better safeguards to guarantee the stability of our electrical supply," he said.

The premier's comments came after the government-owned oil company CPC Corporation said on Wednesday that a flawed power supply replacement process caused the massive power blackout that affected some 6.7 million, or half, of

Taiwan's businesses and homes.

CPC Corporation Chairman Derek Chen told reporters that a contractor, which was hired to replace parts of the power supply system, did not switch the system from an automatic to manual setting.

This triggered the computer system to send the wrong signal, which closed a valve and cut off a natural gas supply to the Tatan power plant in Taoyuan, and caused the power trip at 4.52pm on Tuesday, which lasted two minutes.

To restore normal power supply, the government rationed electricity for three hours across the island, causing the widespread blackout. But the power outages did not affect high-speed rail and metro train services.

Mr Chen, who apologised for the operational error, said that the oil company will compensate any losses incurred by Taiwan's government-owned utility, Taipower.

Economic Affairs Minister Lee Chih-kung tendered his formal resignation on Wednesday morning and Premier Lin said that Mr Lee's deputy Shen Jong-chin will take over as acting minister.

Lawmakers have also called on the top executives at the oil company and utility to also step down.

This is one of the worst power outages in Taiwan in nearly two decades. A huge earthquake in 1999 caused massive power outages for about three weeks.

Recent incidents have also put Taiwan, which is experiencing a heatwave, at risk of a power shortage. This included the collapse of a power transmission tower from a typhoon and the breakdown of a power plant.