* 2014 net loss A$355.6 mln vs A$98.1 mln in 2013
* No earnings guidance
* Sells stake in frequent flyer program to private equity (Recasts, adds earnings details)
SYDNEY, Aug 29 (Reuters) - Virgin Australia Holdings said its annual net loss tripled, hit by excess market capacity and one-off charges, adding that it would not give guidance for the current financial year because of an "uncertain economic environment."
Virgin and rival Qantas Airways Ltd have been engaged in a bitter price war in an attempt to increase market share.
Virgin also said weak consumer sentiment, a now-defunct tax on carbon-emitting companies and a charge for the 60 percent stake it bought in budget domestic carrier Tigerair last year had helped widen losses.
Its net loss for the year to end-June was A$355.6 million ($333 million), compared with A$98.1 million net loss for the previous year.
The company said its underlying net loss of A$211.7 million was in line with analysts' forecasts.
Virgin revealed its loss a day after Qantas reported an unprecedented A$2.8 billion net loss, although Qantas' loss was mainly due to a large restructuring. Qantas reported an underlying loss before tax of A$646 million, better than analysts had expected.
Virgin also said it is selling a 35 percent stake in its frequent flyer program to private equity firm Affinity Equity Partners in a deal which values the unit at A$960 million.
Virgin shares closed at A$0.42 on Thursday. (1 US dollar = 1.0687 Australian dollar) (Reporting by Byron Kaye; Editing by Edwina Gibbs)