Qantas has suffered a $4 billion revenue hit from the coronavirus crisis and warns international travel could still be a year away.

The airline reported an underlying profit before tax of $124 million for the 2019/20 financial year – a 90.6 per cent decline – compared to $1.33 billion the year before.

Qantas group CEO Alan Joyce said the second half of the year was the toughest set of conditions the national carrier had faced in its 100-year history.

“The impact of COVID on all airlines is clear,” he said on Thursday.

“It’s devastating and it will be a question of survival for many.”

It had scored a $771 million pre-tax profit in the first half of the year before things fell apart.

“(The results) reflects a strong first half of the year, followed by a near-total collapse in travel demand and a $4 billion drop in revenue in the second half due to the COVID-19 crisis and associated border restrictions,” Qantas said.

The national carrier’s statutory net loss was $1.96 billion.

On a pre-tax basis, the loss was $2.7 billion, including aircraft writedowns.

The carrier says given current border restrictions, 20 per cent of pre-COVID domestic capacity is scheduled for August.

Recent sales activity shows there will be high levels of demand when those restrictions are eased.

But its international network is unlikely to restart before July 2021, although a Trans-Tasman route could start earlier.