Former MP Georgina Beyer has confirmed she has been diagnosed with chronic kidney failure.
Ms Beyer says she was diagnosed in April and is going into hospital this week for surgery in preparation for getting kidney dialysis.
She says she will need dialysis four times a day, and is also on the waiting list for a kidney transplant.
As a result, Ms Beyer says, she will not be able to contest the Wellington mayoral election in October as she had hoped.
Georgina Beyer says the news is disappointing but she has to face it.
When she was elected in 1999 Ms Beyer was world's first transsexual member of parliament. She served as a Labour Party MP until 2007.