The island is in mourning after the Black Hawk carrying the chief of general staff Shen Yi-ming and seven senior officers smashed into the mountains near Taipei on Thursday, just days ahead of national elections.

The general and his entourage were on a routine mission to visit soldiers in the northeast for the upcoming Lunar New Year.

Investigators located the military helicopter's flight data recorder on Friday and it will be analysed to help determine the cause of the crash, the defence ministry said.

Shen, 62, was the highest-ranking Taiwanese military official to die while on duty.

Flags at all military units have been at half mast since Thursday.

The UH-60M helicopter was carrying 13 people in total, with five surviving the crash. It disappeared from radar less than 15 minutes after taking off, and did not send a distress call before it perished.

Taiwan has grounded more than 50 Black Hawks in military and government service for safety checks.

The crash comes ahead of January 11 polls, when the island will elect a new president and parliament.

China claims the self-ruling, democratic Taiwan as part of its territory, to be taken by force if necessary.

Beijing-sceptic President Tsai Ing-wen is seeking a second term, looking to fight off a challenge from Han Kuo-yu, who favours warmer relations with China.

Both camps have suspended campaigning for two to three days after the crash.

Tsai paid her respects to the victims at a makeshift shrine in Taipei on Friday, and visited the survivors in a hospital before holding a top-level military and national security meeting.

"This incident is a huge loss for our country. We are in mourning... but we cannot relax for one single day on... national security," she told officials at the meeting.

Beijing has stepped up military and diplomatic pressure on the island since Tsai took power in 2016, as her party refuses to acknowledge that Taiwan is part of "one China".