Australian researchers will head to East Timor to teach local specialists how to protect much-needed crops from disease and pests amid a food shortage.

Lack of food is threatening to destabilise the troubled nation, with the World Food Program (WFP) estimating a production shortfall of 30 per cent in staple grains.

A severe shortage of rice in February this year raised concerns, and the WFP believes up to 220,000 people, or one-fifth of the population, will be suffering from severe hunger and need emergency food aid by October.

Australian airline Virgin Blue Holdings almost doubled its full-year earnings after attracting more corporate travellers, helping offset rising fuel bills.

Virgin Blue, Australia's second-largest airline, said it expected further revenue growth this year but also higher costs as it sets up new services in New Zealand and to the United States.

Net profit for the year to June 30 was $216 million compared with $112 million a year earlier. Net profit before one-off items was $232 million.

This compared with analyst expectations of $204.4 million, according to the mean of 9 forecasts on Reuters Estimates.