Russia's Interfax news agency quoted an unnamed source within Russia's Roscosmos Federal Space Agency as saying an American and a Russian would take part in the one-year mission that would be twice the duration of current deployments to the ISS.
NASA responded by saying such a mission hasn't gone beyond the talking stage.
"We are exploring the idea of a one-year increment as part of preparations for exploration beyond low-Earth orbit," NASA spokesman Kelly Humphries of Johnson Space Center in Houston told SPACE.com. "But the discussion is very preliminary and no official decisions have been made."
Spending a year on the space station could give scientists an opportunity to study long-term effects of spaceflight such as would be experienced by astronauts on a mission to Mars, which would likely take two years to complete, SPACE.com said.
Gal Gadot cast as Wonder Woman for 'Batman vs. Superman'
Toddler uninjured after being knocked over by Obama family dog