Fly from New Plymouth Airport (NPL) to Auckland (AKL) on Air New Zealand, then connect to a direct flight from Auckland to Perth (PER) on Air New Zealand or Qantas. Total flight time approximately 11-13 hours including layover. Typical departure early morning to arrive evening Perth local time.
Alternatively, take a morning flight from New Plymouth to Wellington (WLG), then connect via Auckland to Perth with Air New Zealand or Qantas. Longer transfer but flexibility for preferred timings.
Fly Adelaide to Sydney with Qantas (approx. 2h), then Sydney to Auckland with Qantas or Air New Zealand (approx. 3h), finally Auckland to New Plymouth on Air New Zealand (approx. 1h). Total around 8-9 hours plus layovers.
Fly Adelaide to Melbourne (approx. 1h30m), Melbourne to Auckland (approx. 4h), Auckland to New Plymouth (approx. 1h). More connection but flexible timings.