A woman who went missing in Mandurah on Monday morning has been found wandering outside WA Police headquarters in the Perth CBD.

Mary Cummins, 80, was last seen walking near Hungerford Avenue and McLarty Road in Halls Head at around 9am and was reported missing to Mandurah police.

Mary with lamingtons, acup of tea and a WA Police officer. Credit:WA Police

Ms Cummins niece said she immediately started searching for her aunt.

"The last they'd seen her was 8.40am and I got the call at twenty past nine," she said.