Japan and the two countries signed a treaty in December formalising plans to pool resources to co-develop the fighter jet they hope will take to the skies by 2035.

Japan's arms export rules currently forbid the export of equipment to a third country, although there have been exceptions in recent years.

Yosuke Takagi, policy chief of coalition partner Komeito, said at a meeting with the Liberal Democratic Party that they "have agreed" to ease the rules for exports of the fighter jet.

But each individual export will need cabinet approval and the planes can only go to countries with defence deals with Japan that are not involved in active conflicts, public broadcaster NHK said.

In a poll by Kyodo News released Sunday, 48.1 percent of respondents said the export "should be allowed with limited destinations" and 44.7 percent said it "should not be allowed."