A Jetstar spokesman said if its advert run on a travel industry website implied the on-time performance related to this year, the airline "would have a look at it".
In all its media releases it had stated its punctuality claim related to the full 2014 year, he said.
The Air New Zealand advert is the latest shot at the Qantas group. Air New Zealand last week took out a full-page ad saying it had sent the Australian airline's chief executive Alan Joyce a frequent flier card after he acknowledged the competitor was a good airline.
Here airlines collect and make public data themselves, whereas in Australia this is done by the Government Bureau of Infrastructure, Transport and Regional Economics. The time of departure is recorded from when the pilot releases the handbrake and the aircraft is pushed back.
Air New Zealand has almost double the number of Airbus A320s on its main trunk routes.
"We operate a fleet of 15 A320 aircraft which gives us additional flexibility and better ability to recover flight schedules - for example when both airlines are impacted by weather," a spokeswoman said.
Jetstar has built flexibility into its regional operation which has five Bombardier 50-seat planes and says it has the expertise to operate the new regional fleet efficiently.
"We know that reliability is very important and the facts speak for themselves," said Jetstar chief executive of Australia and New Zealand David Hall.
The airline has been flying the Tasman from Christchurch for a decade and domestic jet routes since 2008 and would consider expanding the new regional operation if demand was sufficient.
"We're in it for the long haul I see it as very much a long-term proposition for Jetstar and for regional tourism. We never say never to growth and if the opportunities are there."
Jetstar took less than six months to get the regional operation up and running and hired another 150 staff on top of the existing 400 workers here. The Napier-Auckland-Nelson service will be followed next February with flights to Palmerston North and New Plymouth.
One passenger aboard the inaugural flight from Napier, Mike Wilkey, said he flew to Auckland for business around two times a month.
He paid $60 return on an introductory fare, compared to a typical prices of $350 on Air New Zealand.
Reliability of service was the most important factor for Wilkey.
"We'll respond as we always do - by bringing our low fares to more Kiwis than ever before."