Health Minister Shane Reti is expected to be demoted in today's surprise Cabinet reshuffle.

Prime Minister Chris Luxon is set to reveal some new changes to personnel and portfolios later this afternoon - and it's believed Shane Reti will be the first casualty of the new year.

Newstalk ZB political editor Jason Walls says Luxon had not planned to do a reshuffle this early in the year, and it's unclear what inspired this change.

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