China has agreed to lend $195 million to Cambodia so it can buy Chinese military helicopters, the latest deal in a flurry of trade and investment between the two countries.

The loan would be for an undisclosed number of Chinese-built Zhi-9 (Z-9) utility helicopters, according to official documents seen by Reuters, which covered some 29 agreements signed on Saturday by the two countries.

The agreement is the most recent in a surge of Chinese investment and lending that has led to concerns that Cambodia could become too dependent on China.

The Z-9 is a license-built version of the French-made Eurocopter AS 365 Dauphin II first used in the 1980s. Much of Cambodia's military equipment is outdated and in need of repair, with only a few helicopters currently in use.

Cambodian defence ministry spokesman Chhum Sucheat could not confirm how many helicopters would be purchased or when they would be delivered.

China last year donated more than 250 jeeps, trucks and ambulances to Cambodia's army after the United States cancelled plans to provide it with 200 vehicles, in response to the government sending 20 ethnic minority Uighur asylum-seekers back to China in 2009.

As well as government-to-government loans, Chinese firms' Cambodian investments are mainly in construction, agriculture, mining and energy.

Chinese companies last year pledged to invest $8 billion in 360 projects in the impoverished Southeast Asian country in the first seven months of this year, almost as much as the country's annual gross domestic product.

Among the deals agreed at the weekend was for China's Huawei technologies to help cellphone operator CamGSM to build Cambodia's first satellite.