Scientists analysing growth rings of 700-year-old native cypress trees in Western Australia's Wheatbelt say the region suffered a series of megadroughts lasting up to 30 years in past centuries.

The study has also suggested the region was comparatively blessed with rain during the 20th century.

Climatologist Alison O'Donnell said rainfall records since 1900 capture "one of the wettest periods in the last 700 years". 

"The worst drought periods that have occurred in this region occurred prior to instrumental records," she said.

Dr O'Donnell from the University of Western Australia and her team were able to piece together a record of droughts and floods back to the year 1350 by looking at tree growth rings from a stand of ancient trees she found on the edge of a salt lake.

Read the article on the ABC website, featuring Prof Nerilie Abram