TOKYO — The government submitted to the Diet on Friday a labor reform bill aimed at addressing Japan’s chronic overwork problem, prompting a countermeasure by opposition parties aiming to come up with their own alternative bills.

Prime Minister Shinzo Abe’s government views the reform of working practices as its most important agenda item in the current Diet session and is seeking passage of the bill by the end of the session through June 20.

The opposition forces claim that the envisioned labor reform legislation could exacerbate long working hours and lead to an increase in “karoshi,” or death by overwork.

Diet sources say that deliberations over the labor reform bill may not start within the month because of a tight schedule for the lower house’s health, labor and welfare committee due to other issues.

The bill was approved by the Cabinet earlier in the day. In the run-up to the approval and submission to the Diet, the government had removed one of the bill’s key pillars after a survey on working hours backing it proved erroneous.

It now consists of three pillars — setting a legal cap on overtime work, ensuring equal treatment for regular and nonregular workers, and exempting skilled professional workers with high wages from working-hour regulations.

Although the ruling camp claims the last item, known as the white collar overtime exemption and sought by business lobbies, would enable “flexible work styles,” opposition parties and labor unions have lambasted it as a “zero overtime pay” scheme.

The opposition parties have also said it is unclear which workers are targeted by the bill and are set to submit alternative bills to the parliament.

The government had initially hoped to expand the “discretionary labor system,” which rewards workers based on a fixed number of overtime hours rather than actual hours worked, but dropped the scheme after numerous errors were found in February in government data designed to promote it.

The bill meanwhile sets the legal overtime cap at 100 hours per month and 720 hours per year and stipulates that companies that violate the limits will be punished. The cap will be introduced at major companies in April next year and smaller firms in April 2020.

The government had sought to submit the bill to the Diet in late February, but the schedule was pushed back due to the flawed data.