Nov. 29 (Bloomberg) -- National Australia Bank Ltd., the nation's largest, agreed to buy U.S.-based Great Western Bancorporation Inc. for $798 million, its biggest acquisition since the 1998 purchase of HomeSide Lending Inc. led to billions of dollars in losses.

National Australia will complete the purchase of Omaha- based Great Western, which has assets of more than $3.4 billion and about 100 branches in the Midwest agricultural region, by June, the Melbourne-based bank said in a statement today.

``If they get it right then it's more evidence that they have managed to come right after some dark years,'' said Jason Teh, who helps manage the equivalent of $5.3 billion in Australian equities, including National Australia, at Investors Mutual Ltd. in Sydney. ``They got their fingers burnt overseas before, and got a lot of shareholders offside. I'd suggest the bank will have been doubly careful about this acquisition.''

National Australia last month posted record second-half profit of A$2.44 billion, helping it win back investor confidence after a currency trading scandal in 2004 and $2.2 billion in writedowns from the acquisition of Florida-based mortgage company HomeSide.

National Australia, which gets about 2.5 percent of its net income from the U.S., said it will use Great Western to target growth in farm lending. Agricultural trade globally has increased 50 percent the past five years, the bank said.

``Great Western Bank offers an ideal springboard to accelerate the organic growth strategy for our agribusiness relationship banking model into the U.S.,'' John Stewart, National Australia's chief executive officer, said in the statement.

Stewart took charge in 2004 when Frank Cicutto quit after A$360 million of currency-trading losses. The company sold HomeSide in 2002 after $2.2 billion of writedowns in 2001 ended eight years of record profits.

National Australia fell 7 cents to A$39.34 at 12:25 p.m. in Australian Stock Exchange trading.

To contact the reporter for this story: Stuart Kelly in Sydney skelly22@bloomberg.net

Last Updated: November 28, 2007 21:12 EST