Prime Minister Yoshihide Suga told his British counterpart Boris Johnson on Wednesday that Japan hopes Britain will reach a deal with the European Union on their future relationship by the end of the Brexit transition period in December.

In their first talks since Suga took office last week, the two leaders agreed to bolster bilateral cooperation, including promoting post-Brexit free trade, the Japanese Foreign Ministry said.

During the 20-minute telephone conversation, Japan also welcomed Britain's interest in joining the Trans-Pacific Partnership regional trade pact, the ministry said.

Many Japanese companies operating in Europe are based in Britain, and without such a deal, their businesses could be disrupted.

Japan and Britain are aiming to implement their trade pact, which largely replicates the existing Japan-EU agreement, in January next year to ensure continuity in their trade and investment relationship.

Suga and Johnson also agreed to strengthen security ties and closely coordinate efforts at realizing a free and open Indo-Pacific region, the ministry said.

The concept promoting the rule of law, freedom of navigation and democracy in the Indo-Pacific was coined by Suga's predecessor Shinzo Abe in a veiled counter to China's rising clout in the region.