Tamaki MP Allan Peachey is understood to be considering standing aside in November as fresh concerns emerge about his health.
Mr Peachey was elected to the safe National seat in 2005 but was diagnosed with cancer shortly afterwards.
He recovered after a 12cm tumour and his right kidney were removed but had to take a break of several weeks last year after a lung collapsed.
This year he contracted septicaemia which affected his appearance, but more recently appeared in Parliament bald.
At the time, he told the Herald he was not receiving chemotherapy but had shaved his hair off "for a reason" and would not comment on his health.