The incident centred on the Russian-built Zvezda module which provides living quarters, Russian media report.
The ageing space station has suffered a number of failures over the years and a Russian official recently warned of outdated hardware and failing systems.
These include air leaks, misfiring engines and cracks.
Russia's space agency, Roscosmos, said later that all systems were back to normal.
The smoke was detected during recharging of the station's batteries, the agency said, and the crew had now returned to "regular training".
The burning plastic smell was reported to have spread from the Russian section to the US segment.
The US space agency, Nasa, said a spacewalk planned for later on Thursday would still go ahead, according to Russia's Ria Novosti news outlet.
Two Russian cosmonauts are set to carry out work on the recently delivered Nauka science module.