The national carrier plans to lay off 1460 cabin crew staff as it burns through $14 million a month in crew salaries with almost no revenue.
E tū head of aviation Savage said the airline had sped into a redundancy process despite having access to the wage subsidy, the government loan, and its cash reserves.
He said union members accepted the scale of the problem but wanted a fair transition.
The airline was risking its good reputation by rushing into this, he said, and risked destroying the company.
Last week Air NZ said Covid-19 had slashed its revenue by more than $5 billion.
In a message to staff, chief executive Greg Foran said international travel made up two-thirds of the company's revenue and that was gone now for the foreseeable future.
The airline is now expecting to earn less than $500m in a year. Before Covid-19, Air New Zealand had annual revenue of around $5.8b and a profit of $374m.
Neither the Government's $900m loan nor the wage subsidy scheme was enough to stave off cutting 12,500 jobs by at least a third, Foran had said.
Citing a 99 per cent drop in domestic travel demand, the airline announced only a handful of return services a day would operate from Auckland, Wellington, Christchurch, Nelson and Dunedin.