Japan's Maritime Self-Defense Force is expected to make the first port call at an upgraded naval base in Cambodia.

Former Cambodian Prime Minister Hun Sen said on Friday that he has extended an invitation to the MSDF after meeting Japan's national security chief Akiba Takeo in Phnom Penh.

Akiba also met current leader Hun Manet, who is the son of Hun Sen, and other officials.

Ream Naval Base is located in Cambodia's southwest. The facility is being expanded with financial support from Beijing.

In 2019, The Wall Street Journal said Cambodia had secretly concluded an agreement that allows China's military to use the facility in return for assistance.

The US government has since expressed concern about Beijing's growing influence in the region.

Observers say leaders in Phnom Penh want to strike a diplomatic balance. They maintain good relations with their counterparts in Tokyo.

Japan has consistently promoted democracy in Cambodia and helped the country develop.