National Australia Bank (NAB) Thursday said it has agreed key terms to acquire AXA Asia Pacific's Australian and New Zealand businesses in a surprise announcement which follows a rival takeover offer.

NAB said AXA Asia Pacific, a financial services group, would recommend the proposal to its shareholders, who can receive 6.43 Australian dollars (5.79 US) per share. AXA closed at 5.65 dollars on Wednesday.

"NAB today announced that it has agreed certain key terms with AXA Asia Pacific for NAB to acquire AXA AP's Australian and New Zealand businesses," NAB, one of Australia's "big four" banks, said in a statement to the stock exchange.

"AXA AP's independent directors will recommend to shareholders that they accept NAB's proposal to acquire all of the shares in AXA AP on terms that value the Australian and New Zealand businesses at 4.6 billion Australian dollars."

The deal is conditional on AXA selling its Asian businesses to French parent AXA SA, which on Monday announced a sweetened 12.85 billion Australian dollar takeover offer along with Australian insurer and funds manager AMP.