There has been record breaking rain in the ACT region in the past 24 hours.

Since 9am on Monday, Canberra has received 58millimetres, and Tuggeranong recorded 73mm.

The rain gauge at Mount Ginini had 77mm, Braidwood 60mm and Perisher 42mm.

It is the most rain which has fallen in Canberra in one day since March 2012.

The heavy rain did cause some problems with minor flooding and fallen trees in Canberra's south, but there are no reports of major damage.

Weather bureau forecaster Sean Carson says such heavy rain is highly unusual for this time of year.

"For September we've actually never had this much rain at all at this time of year," Mr Carson said.

"Because we tend to associate these very heavy rainfall events with the warmer months because warm air basically holds more moisture in the atmosphere.

"So to do it in September is unprecedented as far as my records sitting in front of me."