The Bureau of Meteorology has issued a flood warning for the Queanbeyan and Molonglo Rivers, with up to 50 millimetres of rain expected in the region over Thursday night and Friday morning.

The banks of rivers are popular with wombats who make burrows there, and many drowned during the last floods in 2010, Wildcare Queanbeyan spokeswoman Miriam Hazel said.

Ones that escaped the flooding could flee into towns, but Ms Hazel warned they should not be approached, as wombats and kangaroos in particular were powerful animals and would be distressed.

Instead, she said that people who came across native wildlife should call the Wildcare hotline, where trained handlers were available to help.

"These wombats are likely to have inhaled water and be in need of immediate assistance or help in the coming days and weeks if they develop aspiration pneumonia."

She also asked that drivers take extra care on the roads, and that wombats can "run faster than Usain Bolt" so to slow down if they see one while driving.

Ms Hazel said the group was being proactive in alerting people to displaced wildlife after the rain, but hoped that the flooding would not eventuate.

She said animals the animals most likely to be displaced by flooding are wombats, kangaroos, lizards, snakes and turtles, and if there are winds then birds, possums and gliders may also lose their shelter.

She said at this time of year snakes were also an issue, especially after after the rain.

If anyone encounters a native animal that is in need of assistance they should call the Wildcare hotline on 6299 1966. The Wildcare hotline operates 24/7. Most of the flooding is expected in the Queanbeyan area but if there are animals in the ACT in need of assistance call ACT Wildlife on 0432 300 033.