The 10th round United Rugby Championship fixture between Dragons and Scarlets becomes the latest game to be postponed due to Covid-19.
The decision was taken because of positive cases reported in the Dragons squad forcing them to remain in isolation.
This was also the third game involving Dragons that was postponed following their fixtures against Ospreys and Cardiff over the last two weekends.
"The game was due to take place on Saturday, January 8 in Llanelli, however, a number of positive Covid-19 cases within the Dragons playing squad have been reported by the region.
"The URC Medical Advisory Group has liaised with the region and having considered all the facts have deemed that the fixture cannot go ahead as scheduled.
"The United Rugby Championship will now consider available dates to reschedule the game."
Dragons' next game will be in the European Challenge Cup as they lock horns with Benetton Rugby on 15th January.