Winston Peters, New Zealand's deputy prime minister, has pledged to be "fighting fit" to contest the September 19 election despite shock surgery.
The New Zealand First leader said he underwent "successful keyhole surgery" for a mystery ailment on Thursday.
Mr Peters sought the advice of a doctor after complaining of "food poisoning symptoms and dehydration" and was advised he needed surgery.
The 75-year-old will now recuperate at home, putting off this Sunday's planned campaign launch in Whangarei for a week.
"This is an unexpected medical event and of course unexpected timing," Mr Peters said in a statement.
"However the doctor's advice on having surgery needs to be followed.
"I remain confident of a quick return to work - as well as being fighting fit for the election campaign, which is typically physically gruelling."
Finance Minister Grant Robertson said Mr Peters "absolutely" remained fit for the hefty workload, while not shining any further light on his condition.
"I don't have any information to add other than to wish the deputy prime minister well," he said.
Mr Peters put out a statement saying he needed surgery at 10am NZST on Thursday and announced it had been successful at 1:30pm NZDT.
New Zealand First is, along with the Greens, one of two minority parties in government with Prime Minister Jacinda Ardern's Labour.
The right-wing party is currently polling at two per cent, well short of the five per cent needed to ensure representation in the next parliament.
Last year, Mr Peters was missing from Wellington and parliament for around a month as he recovered from a surgery which Ms Ardern said was "an old leg issue" related to his rugby-playing days.
Mr Peters refused to answer questions on the injury, saying only his return to health was delayed by an infection.
Australian Associated Press