Solar hot water panels have fallen victim to this weekend's cold snap, bursting, splitting and leaving home owners with plumbing bills in the thousands.

Plumbers say they have struggled to keep up with unprecedented demand for help as temperatures plummeted. One plumber in Melbourne's west said he had attended eight jobs over the weekend.

A burst solar panel in Lilydale after a frosty weekend in which temperature dropped to minus 5 degrees. Credit:John Willis

Sub-zero temperatures were reported around Melbourne on Sunday, including minus 5.3 degrees at Coldstream, near Lilydale, and minus 2.5 degrees at Viewbank.

The cold snap caused water in panels to freeze and expand, resulting in snapped and split panels and broken frost valves.