The 20-year-old - who started his career at Everton - has made just four appearances for the Fir Park side this season and has been allowed to join in the push for promotion at Dundee.
The Dens Park club were delighted to have secured Cummins' services and intend to bolster the squad further. "Hopefully, he's not the last quality player to join us during the transfer window," said Scot Gardiner, the Dundee chief executive.
The defender could make his debut against Livingston tomorrow, playing in front of goalkeeper Kyle Letheren after he resumed training following concussion. "Kyle would appear to be okay," said John Brown, the Dundee manager.