TechCrunch, citing an unnamed source, said there were concerns among the companies that the hype generated would overload the game. It added that it wasn't immediately clear when the game would be released in Japan.
The phenomenal success of Pokemon Go and the surge in Nintendo Co's market value by $17 billion in just over a week has been seized upon by one of its most vocal investors to press for a change of strategy at the company.
Until Pokemon Go, a mobile game, was launched just over a week ago, Nintendo had taken every opportunity to say its main focus was still gaming consoles, and games for smartphones were just a means to lure more people to them.
Nintendo President Satoru Iwata last year cautioned against hoping for too much change at the company. The expansion into smartphone games was "not because we have lost our enthusiasm or prospects for the console business", he said at the time.
A Nintendo spokesman, asked about its mobile strategy, said last week there were three main objectives: "To maximize exposure of Nintendo's intellectual properties to consumers, to make profits on mobile devices, and to create synergies with the console business."
Written with inputs from Reuters