Several casualties in today's Cabinet reshuffle - with Shane Reti and Melissa Lee both demoted

The Health portfolio's moved from Dr Reti to Simeon Brown, and Dr Reti moves out of his fourth place in the National Party rankings.

He'll instead take over as Minister for Statistics, Universities and Science, Innovation and Technology.

Prime Minister Chris Luxon says it was a difficult conversation, but he needs focus and delivery in health care.

He says Dr Reti's a class act and a total team player, committed to doing an exceptional job with his new portfolios.

Melissa Lee's lost all her Ministerial duties; Nicola Willis is welcoming a new Economic Growth role.

Ms Willis says it's time to unleash the potential of industries, businesses and innovators.

She says we want more investment, new ideas, more people being hired and more exports being generated.