The investigation against him was closed in 2017 but the defense lawyer for one of the female victim's asked prosecutors to reconsider their decision.
Deputy Director of Public Prosecutions Eva-Marie Persson said new circumstances have made it possible to relaunch their work into the investigation.
The case stems from a visit Assange made to Sweden in 2010. Afterwards, two women accused him of rape and other sexual offences though Assange has always denied the claims, saying it was consensual.
Once a Swedish investigation was opened, Assange sought refuge in the Ecuadorian embassy in London, saying he feared Sweden would turn him over to American authorities for publishing classified US documents on Wikileaks.
Assange stayed in the embassy for 7 years until he was kicked out this spring. He's currently serving a 50-week sentence for skipping bail in the UK. He is also wanted in the US for computer fraud.