Kevin Rudd in hospital

FORMER prime minister Kevin Rudd has been admitted to hospital in Brisbane and will have an operation later on Friday.

A spokeswoman for Mr Rudd, who is running for the Brisbane seat of Griffith in the August 21 federal election, said the former Labor leader had experienced acute abdominal pain on Thursday.

He underwent a series of medical tests on Thursday night and Friday morning, she said.

"Based on specialist advice, he was admitted to the Mater Private Hospital around lunch time today," the spokeswoman said.

"Mr Rudd will have an operation to remove his gall bladder later today."

Mr Rudd's doctors had advised he was likely to be in hospital for a couple of days before being allowed home, she said.

"Mr Rudd looks forward to resuming campaign activities next week both in his own electorate, elsewhere in Queensland and the rest of the country as appropriate in support of the re-election of the government and prime minister Gillard," she said.