Wellington: Airlines operating in and out of New Zealand have been warned on Saturday that flights may be disrupted as ash from from Chile's Puyehue volcano reaches the country.

Strong winds have carried ash plumes 9,400 kilometres across the Pacific to New Zealand since the eruption seven days ago and they were expected to spread across the country over the weekend.

The plumes were expected to be at 20,000-30,000 feet, the cruising levels for both jet and turboprop aircraft, the Civil Aviation Authority said.

New Zealand airspace might be affected for at least a week, given that the volcano was still erupting, it added.

Across South America several flights have been cancelled since the volcano erupted for the first time in half a century.