The Basslink interconnector cable is out for the second time in three months.
A Hydro Tasmania spokesperson confirmed on Monday Basslink has been offline since 11am on Saturday.
"We have been advised by Basslink Pty Ltd that they are working to diagnose the issue and return the cable to service as soon as possible," the spokesperson said.
"There is no impact to energy security with current storages at 45.5 per cent."
Infrastructure Minister Michael Ferguson said the state's dams were at a more than adequate level.
"We take energy security very seriously [and] we have increased the prudent water level requirements," Mr Ferguson said.
Bass Liberal MHR Bridget Archer said she was confident in Tasmania's energy security.
"It's really a matter for the company to work through what the issue is and work towards the repair," Ms Archer said.
In the 12 months to June, the interconnector had a total of six outages, four of which were unplanned.
In December 2015, an outage which took 6 months to repair was a contributing factor to the state experiencing an energy crisis.
Basslink was contacted for comment.