Canada Pension Plan Investment Board offered to buy a "significant" minority stake of Auckland International Airport Ltd, valuing New Zealand's busiest air field at as much as NZ$4.76 billion (US$3.5 billion).

The Toronto-based fund manager is offering NZ$3.70 per Auckland Airport share in cash, it said in an e-mailed statement on Sep. 19. Shareholders could also opt for a mix of cash and securities, with an equivalent value of as much as NZ$3.90 per Auckland Airport share, 28 percent more than the shares traded on Sep. 19, Bloomberg News said.

Auckland handles about 70 percent of international arrivals into New Zealand, where the government forecasts tourist numbers will rise 31 percent over the next six years. Canada Pension was left as the only bidder for a stake after state-controlled Dubai Aerospace Enterprises quit plans to acquire control of the airport.

"Everyone would like to have an opportunity to sell at 20 percent above the current share price," said James Lindsay, who helps manage the equivalent of US$333 million at Tyndall Investment Management Ltd in Auckland. "It's a very well-run company that is well-positioned for good growth given the predicted gains in New Zealand tourism."

Canada Pension said it has committed funding and "intends to submit a proposal under which it would acquire a significant minority stake in Auckland" airport. The fund has C$120.5 billion (US$119 billion) as at June 30.

Dubai Aerospace this month abandoned a NZ$2.6 billion plan to buy 51 percent of Auckland International after two city councils with a combined 23 percent holding objected to the sale.