The competition had been due to start this weekend but with 10 positive tests at Kobe Steelers on Thursday taking the total to 67 league-wide, organisers said they were now aiming for a mid-February start.
Last year's season was cancelled entirely because of the pandemic.
"Japan Rugby Football Union and Top League have had discussions and we want to do everything we can to have this year's Top League season," said JRFU Chairman Kensuke Iwabuchi.
