Australia Post has blamed mail delays across Perth on staffing issues and recent elections after customers reported letters taking more than two weeks to get to suburban addresses.
Its usual estimate is one business day delivery for regular mail within the metropolitan area, but some customers have waited 5 to 12 business days.
Marion Steed, of Bull Creek, posted a cheque to Balga on October 4 that arrived on October 21 but she had cancelled it after 10 days.
"It was a 60ï¿½ stamp, a local letter which I thought would get there the next day," Mrs Steed said.
"When you put a cheque in the mail you tend to get a little worried, especially when it takes more than two weeks."
Sue Spencer, of Forrestfield, posted a birthday card on Monday, October 14 and it arrived in Oakford seven business days later.
"It made me think maybe I shouldn't have wasted 60Â¢ and just given it to her myself," she said.
Her colleague Valerie Bone sent a letter from South Perth on a Friday this month and it arrived in Bull Creek the next Wednesday. When she complained, she was told of staffing problems in the mail sorting department.
An Australia Post spokeswoman said it had been busy in WA recently, partly because of the local government and Federal elections.Customers with specific concerns about mail delivery to be investigated could call 13 13 18.