The government and the ruling parties have floated a plan to extend the current Diet session by 10 days amid heated debate over a review of the immigration control law to allow more foreign laborers, sources close to the matter said Wednesday.

The government and the ruling coalition led by the Liberal Democratic Party are seeking to secure passage of the bill during the extraordinary Diet session by extending it to around Dec. 20, but the plan is certain to face objections from opposition lawmakers who have criticized the bill for lacking detail.

"It is better to extend (the Diet session) to around Dec. 20," said an LDP Diet Affairs Committee source, expecting that the debate between the ruling and opposition parties will escalate.

Deliberations on the bill, which would enable manual workers from abroad to stay in Japan permanently to address the country's serious labor shortage, started Tuesday in the House of Representatives.

The government disclosed Wednesday estimates of foreign workers it would accept over five years for the 14 industrial sectors targeted by the bill, but it was rebuked by opposition parties who said the figures were groundless.