Greens senator Scott Ludlam has announced he will be taking leave from his parliamentary duties to deal with long-term mental health issues.

The WA senator, a co-deputy leader of the minor party, revealed his decision on Friday, saying he would return "as soon as I'm able to give the commitment the work demands".

Former Australian Greens Senator Scott Ludlam. Credit:Jacky Ghossein

"I am taking a leave of absence to treat depression and anxiety. These are issues I've been dealing with for a while," he wrote on Facebook.

"The team in my office will continue to support and work for the constituents of WA, and work with my Senate colleagues to manage my portfolio responsibilities."