Feb 18 (Reuters) - Australian biotech CSL Ltd on Thursday reported a 45% rise in half-year profit, boosted by higher demand for its vaccines and blood plasma products.

CSL, which is also manufacturing the bulk of the local supply of the AstraZeneca COVID-19 vaccine that got provisional approval on Tuesday, reiterated that the first doses will be released in late March.

The biotech giant reported a net profit after tax of $1.81 billion for the six months ended December, up from $1.25 billion last year. On a constant currency basis, profit came in at $1.79 billion.

The key to CSL's business is its ability to collect blood from donors and convert it into medical treatments, which has been hindered by the pandemic.

But strong demand for plasma and recombinant therapies as well as its influenza vaccines had prompted CSL to raise the lower end of its full-year profit forecast last October.

It still expects profit between $2.17 billion to $2.27 billion, implying growth of 3% to 8%.

CSL, one of Australia's largest listed companies with operations from Germany to the United States, declared an interim dividend of $1.04 per share, up from $0.95 last year. (Reporting by Nikhil Kurian Nainan in Bengaluru; Editing by Bernard Orr and Shailesh Kuber)