The rains that drenched the south-west NSW on Friday and Saturday and put an end to the heatwaves that have battered eastern Australia were forecast to head north, as news came that the federal government would expand drought assistance to hard-hit areas.

In Canberra, rain fell for much of Saturday morning and early afternoon, dumping more than 15 millimetres in the city and 22 in Tuggeranong by 7pm, with mixed falls across surrounding areas.

Scattered showers were forecast to continue on Sunday, with the chance of thunderstorms.

The return of soaking rains lit up Billy Mccosker's smile as he worked the parched land of Karlton Park farm near Sutton on Saturday.

The heavens couldn't open up soon enough for the young zucchini picker and his boss,

property owner Ikebal Patel, who had watched on as his cattle struggled, starved of good feed and a lack of sustained rain.

But the downpour in Canberra and the region on Saturday has reinvigorated Mr Patel and his handful of workers, who manage the property's zucchini, lucerne, hay, cattle and sheep.

''It's put life back into the farm,'' Mr Patel said on Saturday.

''We had a few times when it came tantalisingly close and the clouds were there … so we are very grateful to get it,'' he said.

That relief was expected to spread to farmers in the drought-affected parts of north-western NSW in coming days.

Clear weather and slightly warmer temperatures are expected to return on Monday, before a forecast return of showers on Tuesday.

The rains swelled the ACT's storm water drains on Sunday and sparked police warnings about the dangers of playing in fast-moving waterways.

ACT Policing Superintendent Justine Gough said water levels could rise quickly and parents and children should stay clear to avoid potential disaster.

''We haven't had to respond to an incident of anyone falling in, however, we have attended to waterways where children are playing,'' she said.

The wet weather also caused problems on ACT roads.

Just before midday, a man in his 20s crashed into a light pole on the Tuggeranong Parkway, bringing the pole down across parts of the busy thoroughfare.

It caused major traffic delays and resulted in several rear-enders on the wet 100km/h road.

The weather also caused some consternation for organisers of the Canberra Symphony Orchestra, who decided to push ahead with their Prom Concert on the grounds of Government House on Saturday evening, despite the gloomy weather.