May 11 (Reuters) - Graincorp Ltd raised its annual earnings guidance on Thursday, encouraged by strong demand for Australian grain and oilseeds and upbeat performance in its oilseeds business, sending the agribusiness firm's shares 8.2% higher.

The company now expects fiscal 2023 net profit after tax of between A$220 million ($149.23 million) and A$260 million, up from prior forecast of between A$180 million and A$220 million, it said in a statement.

That guidance compares with a net profit after tax A$380 million posted last year.

"We are seeing good global demand for Australian grain and oilseeds and expect the strong export program to continue in the second half," Graincorp CEO Robert Spurway said.

"Our Oilseeds business is performing exceptionally well with high volumes and crush margins."

Shares of the firm gained as much as 8.2% to A$7.680, their best intraday gains since Oct. 31 and highest level since March 10.

The Sydney-based firm expects earnings before interest, taxes, depreciation, and amortisation of A$500 million and A$560 million in fiscal 2023, above earlier expectation of between A$470 million and A$530 million.

For six months ending March 31, Graincorp's net profit after tax declined 18.6% to A$200.3 million, while revenue jumped 18.2% to A$4.54 billion.

Graincorp also declared an interim dividend of 14 Australian cents per share and a special dividend of 10 Australian cents apiece.

($1 = 1.4743 Australian dollars) (Reporting by Sameer Manekar in Bengaluru; editing by Uttaresh Venkateshwaran and Rashmi Aich)