Flood warnings issued for WA's south

Flood warnings have been issued for parts of Western Australia's south, with heavy rainfall forcing the closure of several roads.

The Bureau of Meteorology warned of rainfall of up to 60mm in parts of the Lower South West and the Great Southern Districts on Wednesday.

A BoM spokeswoman told AAP Franklin had received more than 70mm in the 24 hours before 9am on Wednesday, with further rainfall predicted.

"The reason we've got this is because of a low pressure system near Perth and it's producing slow-moving areas of rain and thunderstorms over southern parts of the South West land division," she said.

One lane of the Albany Highway has been closed, between Collie-Changerup Road and Kojonup, while parts of Broomehill-Jerramungup Road are also closed.

The low pressure system is expected to move southeast on Wednesday evening with heavy rainfall predicted to continue.