The Remuneration Authority says the Prime Minister's pay increase is fair.

Chris Luxon's turned down the $50,000 salary boost over three years, and promises to donate it to charity.

Chair Geoff Summers says a lot of work's gone into determining the figure - including job comparisons.

He says our MP pay is relatively low internationally.

"It's behind most other Westminster democracies - we had a good look at that, the tables are in the report. They're even behind most of the state MPs in Australia, except for Tasmania."

Chris Luxon's salary would riss from $471,000 to $520,000 in 2026.

Normal MPs' 163-thousand-dollar pay packets would rise to $181,000.

LISTEN ABOVE