Investors responded positively to Qantas Airways' interim results showing flat pre-tax profits of $771 million in the six months to December 31 despite a warning the coronavirus outbreak could shave up to $150 million to full-year earnings.

Shares in the company were up about 6.2 per cent to $6.69 in early trade, as revenue also increased 3 per cent to $9.5 billion on the corresponding prior period.