Details of the offer will not be released until union members have been briefed of the outcome, E tū said in a statement.
Talks concluded between the two parties at Air New Zealand headquarters at 10pm and the member's core aims have been largely achieved, the union said.
"Industrial action of this nature is always a last resort and so it's a positive sign that we've reached an agreement in principle," Savage, head of aviation for E tū, said.
"Unions are democratic organisations so the most important next step is communicating with our members.
"We will be recommending the deal to members at ratification meetings over the coming week – then it's up to the members to discuss and vote on the company offer."
On the Friday alone, Air New Zealand has close to 42,000 customers booked to travel domestically on its A320 jets and internationally faced potential flight cancellations.
The airline had accused just under 1000 engineers of deliberately using Kiwi families' much-anticipated Christmas holidays as a bargaining chip.
It detailed the average income of maintenance engineers, logistics and other staff to strike — $115,000 – angering unions who accused it of taking an unnecessarily aggressive approach.