Japan's Toyota Motor Corp and Germany's Daimler AG plan extensive cooperation in the field of fuel cells for electric cars, the Financial Times Deutschland reported, citing unidentified sources.
The partnership could take the form of a joint venture, the paper said.
A Toyota spokesman said the automaker had no new cooperation deal to announce now. Daimler, the maker of Mercedes-Benz cars, was not immediately available for comment.
Most major automakers are working on developing affordable hydrogen fuel-cell vehicles as an environmentally friendly alternative to today's combustion engine cars as they emit only water vapor and have a long cruising range, unlike battery-run electric cars.
The biggest hurdle has been the high cost of fuel cells, which require heavy use of platinum and other pricey metals to produce electricity.
Automakers including Daimler, Toyota, General Motors Co GM.UL, Ford Motor Co, Honda Motor Co, Nissan Motor Co and Hyundai Motor Co agreed last year to work together wherever possible to promote the spread of fuel-cell cars from 2015.
The high development costs associated with trying to bring fuel-cell powertrain technology to production means that it is a highly logical step for Daimler and Toyota to try and share the costs and their extensive knowledge in fuel-cell technology, Tim Urquhart, an analyst at IHS Global Insight, wrote in a report.
He noted that Daimler had already invested $1.23 billion in fuel-cell technology since it began its programme in 1994, while Toyota has been developing the technology since 1992.
Toyota and Honda became the world's first automakers to put hydrogen fuel-cell cars on the road in 2002.
Toyota, the world's biggest automaker, last week said it would invest in Tesla Motors Inc to cooperate with the California start-up in the development of electric cars. Daimler also holds a minor stake in Tesla.
Toyota said then that there were no other joint projects being discussed with other automakers.
(Reporting by Yumiko Nishitani and Chang-Ran Kim; Editing by Chris Gallagher)