* H1 profit rises 23 pct to A$617 mln, despite currency hit
* Swine flu vaccine helps offset drop in Gardasil royalties
* Sees year profit at upper end of 14-24 pct rise, constant $ (Adds details)
MELBOURNE, Feb 17 Australian biotherapies group CSL Ltd (CSL.AX) stuck to its full year profit forecast after reporting a 23 percent rise in first-half profit, which beat broker forecasts despite a currency hit.
Its first-half profit was bolstered by sales of the H1N1 swine flu vaccine and seasonal flu vaccine sales to the United States and Germany, which offset a drop in royalties from its HPV cervical cancer vaccine.
CSL, which competes against Baxter Healthcare (BAX.N) and Spain's Grifols (GRLS.MC), said it still expects a full year profit between A$970 million and A$1.07 billion based on current rates, or toward the upper end of a 14-24 percent rise based on last year's exchange rates.
Analysts are expecting a flat profit this year, based on their own currency assumptions, as the group has been buffeted by a weaker U.S. dollar, with the bulk of its earnings from offshore.
In the second half it also faces shrinking demand for the swine flu vaccine and falling royalties on its HPV cervical cancer vaccine, sold as Gardasil by Merck & Co (MRK.N) and Cervarix by GlaxoSmithKline (GSK.L).
A risk investors have yet to factor into CSL's shares stems from an expanding class action brought by U.S. hospitals, joined last week by the prestigious Mayo Clinic, against CSL and Baxter, alleging that they colluded to control plasma products prices.
CSL has repeatedly said it believes there is no substance to the allegations, first made last year by the U.S. Federal Trade Commission when it blocked CSL's $3.1 billion bid for smaller U.S. rival Talecris Biotherapeutics TLCR.O.
CSL Managing Director Brian McNameee said the group's result in the first-half reflected a tough market.
"This is a pleasing result in what has been a competitive trading environment," he said in a statement.
Net profit before one-offs rose to A$617 million ($556 million) for July-December from A$502 million a year earlier, well ahead of analysts' forecasts of around A$526 million.
Gardasil sales fell A$66 million from a year earlier, reflecting the end of an immunisation catch-up programme in Australia. H1N1 flu vaccine sales contributed A$160 million.
CSL's shares have fallen 2.7 percent over the past six months against a 5 percent gain in the broader market. (Reporting by Sonali Paul; Editing by Jeremy Laurence)