South Australia has been reconnected to the national electricity grid more than two weeks after storms damaged transmission lines in Victoria.

Six towers were knocked to the ground near Colac, southwest of Melbourne, effectively closing the Heywood interconnector from January 31.

The interconnector is the main electricity link between South Australia and the eastern states.

AusNet Services confirmed repair work on the first transmission line was now complete, and power was reconnected through the interconnector on Monday.

Work on the second line is progressing, with construction of temporary towers due to start on Tuesday.

Weather permitting, that line should be erected by the end of the week.

When the interconnector went down, the SA government said it highlighted the need for a new interconnector with NSW.

That project was recently approved by the Australian Energy Regulator.