An Air New Zealand spokeswoman said low cloud caused the disruption to services.
One service from Wellington to Rotorua had to divert to Tauranga, two services from Christchurch to Rotorua had to divert to Hamilton and one service from Auckland to Rotorua returned to Auckland.
She said four services out of Rotorua had been cancelled as a result of the diversions.
Rotorua woman Bronwyn Allen was on the Wellington flight diverted to Tauranga.
She said the flight itself was calm and passengers were told around 10am that they would not be landing in Rotorua.
"Everyone took it pretty well, there was no grumbling because it is what it is. We got to Tauranga at about 10.30am and was on the bus bound for Rotorua within five or so minutes.
"It was all very well organised and in the end we got to Rotorua by about 11.30am so there wasn't much delay."
Weekend weather:
- Saturday: Periods of rain. Strong northerly easing, westerly later. High 14C, low 10C
- Sunday: Showers easing later. Westerlies. High 15C, low 6C