Japan and China have sparred over the release of treated water containing tritium from the meltdown-stricken Fukushima No. 1 nuclear plant into the sea at an annual meeting of the International Atomic Energy Agency that opened Monday.

A total of 177 member countries will discuss issues such as nuclear development by Iran and North Korea at the nuclear watchdog's five-day general conference through Friday at its headquarters in Vienna.

In a general debate speech delivered at the meeting, the Chinese representative referred to the treated water from Tokyo Electric Power Company Holdings's plant in Fukushima Prefecture as "nuclear-contaminated water," and reiterated the country's opposition to the discharge.