TOKYO (AFP) - Two Japanese satellites will be launched from Russia to monitor environmental damage near the crippled nuclear plants in Fukushima and Chernobyl, officials said.

The Ukrainian-designed Dnepr rocket carrying 33 satellites, including the two, will lift off at 1911 GMT (3:11am on Friday, Singapore time) from a space centre in the Urals region.

The University of Tokyo developed the two satellites - the Hodoyoshi-3 and Hodoyoshi-4 - on a relatively slim budget of 300 million yen (about S$3.7 million) each.

"The satellites have a number of missions and monitoring the two nuclear plants is part of them," said project leader Mr Shinichi Nakasuka, a professor at the Japanese state-run university.

Under the plan, the two satellites will take photos of the two nuclear power plants and their surroundings regularly receive data, including radiation levels, from instruments near the two plants.

"I hope that the data will help Japan and Ukraine correctly acknowledge the impact on the environment near the two plants," Mr Nakasuka said.

The two satellites will also monitor river levels globally, and "22 countries such as Japan, Vietnam, Thailand and Bangladesh will receive the data as part of efforts to avoid damage from major floods," he added.

The launch, which had been planned for last year, fell behind schedule, but Mr Nakasuka said the delay was not caused by the political situation in Ukraine.

The world's worst civilian nuclear accident took place in Ukraine in 1986, at the Chernobyl nuclear power station. Thirty people were killed in an explosion and a further 2,500 died of related illnesses.

In March 2011, a massive earthquake and tsunami hit Japan's northeastern region and sent nuclear reactors in Fukushima into meltdown.

Full decommissioning of the plant at Fukushima is expected to take several decades. An area around the plant remains out of bounds, and experts warn that some settlements may have to be abandoned because of high levels of radiation.