Taiwan leader Ma Ying-jeou on Monday urged local defense authorities to reflect on a recent scandal where civilians, including a Japanese national, visited an Apache attack helicopter in clear violation of military regulations, local media reported Monday.

Ma expressed grave concerns over recent violations of military regulations and enjoined the "Ministry of National Defense" to immediately make self-criticism, Ma's spokesman was quoted as saying by the Taiwan-based Independent Evening News on Monday.

Prosecutors in Taiwan on Sunday started an investigation into a controversial visit by civilians to an AH-64E Apache attack helicopter that was part of a helicopter squadron based in Taoyuan county, the Xinhua News Agency reported.

Lao Nai-cheng, former deputy head of the helicopter squadron, admitted that he gave his sister-in-law's Japanese boyfriend Naoto Hirayama, five foreign domestic workers and 20 Taiwan residents, including TV star Janet Lee access to the military base on March 29 without official approval, the Taiwan-based Central News Agency (CNA) reported Monday.

Lao let visitors access a hangar that houses the Apaches, the most advanced helicopters the army boasts, and even allowed them to board one of the helicopters and take photos. Lee later posted the photos on her Facebook page, which brought the visit to widespread public attention.

Lee became the second civilian to have boarded one of Taiwan's Apaches after Ma Ying-jeou himself, an insider was quoted as saying by the Taiwan-based China Times.

The island's military announced on Friday that Lao and four others would face disciplinary punishment over the incident. Lao has been given a major demerit and removed from his post.

Lee also repeatedly bowed in apology late Sunday after being released by prosecutors.

All military units have been ordered to conduct self-examination meetings on Tuesday.

Niu Chen-zer, a well-known Taiwan film director, was sentenced to five months in jail with a two-year reprieve in November 2014 for bringing Chinese mainland cinematographer Cao Yu into a naval base in Kaohsiung to scout for locations for his new film in 2013, the CNA reported.

Produced by Boeing Defense, the AH-64 Apache is believed to be the world's most advanced multi-role combat helicopter. The helicopters are used by countries including the US, the Netherlands and Japan.