TOKYO (AFP) - Japan's Prime Minister Shinzo Abe urged Thailand's military rulers Monday to return as soon as possible to civilian rule as he met his counterpart and former army chief Prayuth Chan-O-Cha in Tokyo.

The Thai junta chief is in Tokyo after receiving his first invitation from a G7 country since the coup in May, which took place days after democratically elected prime minister Yingluck Shinawatra was ousted by a court ruling following months of street protests.

"Prime Minister Prayuth is making his best effort to recover democracy in Thailand," Abe told a joint press conference.

"Japan expresses its strong expectations for Thailand's national reconciliation and a return of civilian rule as early as possible." Prayuth said Thailand would speed up action towards the creation of a new constitution.

"We plan to hold elections in the end of this year or the beginning of the next year," he said.

"I promise I will build a healthy democracy in Thailand." The two sides signed a memorandum on cooperation over railway development in Thailand, while "affirming the importance" of promoting the Dawei special economic zone project involving Japan, Thailand and Myanmar, a joint statement said.

Dawei is a multi-billion-dollar seaport project on Myanmar's south coast, which would give Thailand a gateway to the Indian Ocean and Western markets.

The visit by Prayuth came as China is openly courting Thailand's generals and as strains are beginning to show between the kingdom and its traditional ally the United States following last year's coup.

Washington has been critical of the generals' power grab, calling for the return of civilian rule.

China has also backed the construction on a $12 billion railway from northern Nong Khai province - which borders Laos - to the vast coastal industrial estate of Map Ta Phut southeast of Bangkok.

China hopes the 734-km railway will eventually link its southwestern city of Kunming with Asia's second busiest port of Singapore.