Strong summer demand means the airline will operate 2.2 million seats across its domestic network over the peak December-January period, 90,000 more than the same period last year.
The airline has added more than 180 extra flights between December 21 and December 31 December to get holidaymakers to and from their destinations.
General manager of customer experience Anita Hawthorne said travellers should allow themselves plenty of time and to consider taking out travel insurance.
"Naturally, our airports are going to be much busier than usual over the holidays and we ask our customers to be patient as we work to get them to their destinations on time,'' she said.
"We're doing all we can behind the scenes to ensure a seamless customer experience with additional staff rostered on, including 350 corporate employees who have volunteered their time to support their airport colleagues and get our customers to where they need to go.''
She said passengers should allow extra time to get to and through airports throughout the country and sign up for the airline's travel alerts.
Auckland Airport has also warned of possible congestion over the holiday period and says passengers should allow an extra 30 minutes to get through the international terminal.
A spokeswoman said the terminals and roads leading to the airport were busy today but there had been no hold ups reported.
About 19 million passengers use the airport a year and in the latest quarter international passenger growth is up 5.4 per cent and domestic passenger increases up 6.1 per cent compared to same quarter a year before.
Read more: Behind the scenes at the $1.8b airport rebuild
It is undergoing a major rebuilding programme with newly built parts of the international departure area just opened.
Queenstown Airport will also be busy this summer. This week it passed the two million passenger mark for 12 months, a record for the airport.
