Virgin Group boss Richard Branson says Qantas sought financial help from the federal government so it could flood the market with flights and drive Virgin Australia out of business.

The British billionaire said Qantas only needed help when it went "cap in hand" to the government in early 2014 so it could continue to fund a capacity war with Virgin.

"They poured hundreds of millions of dollars into overcapacity into routes we were flying on, and they literally almost drove themselves out of business," Mr Branson, whose group owns 10 per cent of Virgin Australia, said at the launch of Virgin's new Melbourne to Hong Kong service on Wednesday morning.

"Government quite rightfully told them it's up to them to compete on a fair, level playing field. And they went back and stopped dumping tonnes of capacity on routes and behaving more sensibly.