Mrs Singer booked her daughter's flight last Monday after she was only given a few days notice that she had to be back on board the boat by Wednesday.
She looked at whether it would be cheaper to fly on another day but said the difference was only $20.
Herald investigations yesterday showed the cheapest Air New Zealand flight from Taupo to Nelson one-way for an adult next week would be $297.
The lowest airfare from Auckland to Nelson during the same period would be $199.
The lowest fare from Auckland to Sydney was $170 on special or $390 return, and the cheapest standard flight was $278 one way.
The cheapest flight to the Gold Coast flying Virgin Australia was $234.
Tessa Singer, 27, has been commuting between Taupo and Nelson for eight years, but this was the most her mother recalled ever paying for a flight, even at short notice. The flights had previously been around $300.
"They just seem to be getting dearer and dearer," Mrs Singer said.
"Some of those flights were $500/$550 or $600 just one way ... It's just frustrating being stuck with one bloody airline, Air New Zealand. There's no competition."
An Air New Zealand spokeswoman said comparing the cost of travelling from Taupo to Nelson to the cost of travel to Australia was not a fair comparison as there were several factors, including operating costs and passenger demand, that determined fare costs.
The journey between Taupo and Nelson was not direct and there were additional costs associated with landing at an intermediate port combined with using the smaller turboprop aircraft, she said.
"In comparison, Air New Zealand operates larger jet aircraft on its transtasman services which have relatively lower operating costs, shared between considerably more customers, and as a result we are able to offer a higher volume of entry-level fares on this route."
The airline said entry level fares between Taupo and Nelson - $189 according to Air New Zealand's website - were cheaper than those between Auckland and Australia, excluding the current sale on transtasman services.
University of Auckland professor of economics Tim Hazledine, who produced a report comparing regional airfares in several countries including Australia, Canada, Norway and Scotland, did not believe high fares on regional routes was a systemic problem after his own findings concluded New Zealand had much cheaper airfares than overseas.
Professor Hazledine said people wanting to book two or three days before they flew would always face higher prices as the tickets were targeted at the business market and often only limited seats were left.
