MANILA - The Senate will look into China’s 40 percent stake in the the country’s lone power transmission line after lawmakers raised “deep concerns” that it might affect national security, Senate Energy Committee chair Sherwin Gatchalian said Tuesday.

Budget deliberations in the Senate revealed that the State Grid Corp. of China allegedly changed portions of National Grid Corporation of the Philippines' (NGCP) system instructions into Chinese and allowed Chinese nationals to operate the machines.

Under NGCP’s contract, only Filipinos are allowed to operate machines while its Chinese stakeholder can only provide technical assistance.

“I think Congress swill exercise its oversight dahil sa interpellations kanina,” Gatchalian told ABS-CBN News.

The probe will happen within the year, he said, after energy officials confirmed that the Chinese firm can switch off the country’s power grid remotely.

Should this happen, Philippine authorities can reboot the system between 24 and 48 hours after it was hacked, Gatchalian told other lawmakers.

• Senators raise concerns over China's 40-pct stake in NGCP

Senator Richard Gordon said policies should be amended to ensure that the Philippines is “in control” of vital infrastructure, including its lone power grid.

“If you (senator) go there and you cannot enter because Filipinos will be fired by Chinese, then we are not in control,” he said.

“Ang gusto ko lang in control tayo definitely,” he said.

“Clearer, stronger and more enforceable safeguards” should be incorporated in the NGCP’s system, Senator Risa Hontiveros said in a separate interview.

“Inamin naman ng Department [of Energy], through the sponsor, na other actors could take down our system by remotely accessing it, paralyzing it,” Hontiveros said.

“National security concern talaga... Something as vital [as power grids] should be in state hands, in Filipino hands exclusively,” she said.

The Senate Energy Committee has to “carefully study” how the possible revocation of NGCP’s franchise could affect power transmission in the country, Gatchalian said.

“If we amend, we have to make sure that government will be freely allowed to exercise review, oversight functions,” he said.

Gatchalian admitted that foreign investors might be discouraged by the Senate’s move to study the revocation of a franchise, but said: “This is national security. It is supreme over any business consideration.”

Last week, Senate Energy Committee chair Sherwin Gatchalian vowed to investigate the issue.

The committee has to “carefully study” if there were violations and how the possible revocation of NGCP’s franchise could affect power transmission in the country, Gatchalian told ABS-CBN News.

“If we amend, we have to make sure that government will be freely allowed to exercise review, oversight functions,” he said.