Under the tie-up, which was decided at a board meeting on Wednesday, Toyota will invest around 96 billion yen ($910 million) in Suzuki to take around 5% of the smaller automaker, NHK and the Nikkei newspaper reported. Suzuki in turn will invest about 48 billion yen in Toyota, the two outlets said.

Suzuki declined to comment. A Toyota spokesman said the reports were not based on the company's announcement.

The automakers in 2016 said they were exploring a partnership, citing technological challenges and the need to keep up with consolidation in the global auto industry.

Suzuki, which specialises in affordable compact cars, had been struggling to keep pace with the huge costs of investing in research and development for automated driving functions.

The pair earlier this year announced a tie-up to produce electric vehicles and compact cars for each other to better compete with fast-changing technologies in the global auto industry.