Tas hydro dam levels up after rain

Tasmania's hydro-electric dam levels have received another much-needed boost thanks to substantial rain during the past week.

The combined capacity had reached 20 per cent on Monday, which was up 3.9 per cent from the preceding seven days, Energy Minister Matthew Groom said.

Tasmania brought in back-up diesel generators to keep the lights on while dams were low and a Bass Strait electric cable has been inoperable.