Japan's Diet has enacted a bill that allows nuclear power plants to operate beyond the current limit of 60 years.

The legislation was approved at the full Upper House session on Wednesday by a majority vote, with support from the ruling Liberal Democratic Party and its junior coalition partner Komeito and other parties.

The Lower House of the Diet had passed the legislation in April.

Under the revision, nuclear power plants can remain operational beyond the 60-year cap, excluding the time spent to undergo inspections and testing.

The revision calls for power plant equipment and devices to be inspected for deterioration every 10 years or less, once it has been in operation for 30 years.

Plant operators will also be required to draw up management plans and receive approval from the Nuclear Regulation Agency.

The nuclear watch dog approved the plan by a majority vote in February, with one of its five members having voted against it. It is rare for the regulator to decide on key issues without a unanimous vote.

This prompted the government to delay its initial plan and approve the bill at the Cabinet at the end of February in an effort to dispel public concerns.

During deliberations in the Lower House, the ruling parties agreed to add some provisions following negotiations with Nippon Ishin Japan Innovation Party and Democratic Party for the People.

One of the provisions requires the government to seek cooperation from residents in urban areas that consume a large amount of electricity.

With the passage of the bill, citizen groups who oppose it gathered in front of the Diet building and protested.

A member of an environmental group said the enactment means that the government is making a major turnaround in policy in favor of the nuclear power industry.