Metallica postpone NZ tour

Metallica have postponed their upcoming visit to New Zealand and Australia.

Frontman James Hetfield is heading back into rehab, the band said on Saturday.

"We are truly sorry to inform our fans and friends that we must postpone our upcoming tour of Australia and New Zealand," the rest of the band said in a statement.

"As most of you probably know, our brother James has been struggling with addiction on and off for many years. He has now, unfortunately, had to re-enter a treatment program to work on his recovery again.

"We fully intend to make our way to your part of the world as soon as health and schedule permit. We'll let you know as soon as we can."

Metallica, one of the biggest-selling and most enduring rock acts of the past 40 years, were set to play at Auckland's Mt Smart Stadium on October 31 and November 2.

Fans who've already bought tickets will get full refunds - details are on the Live Nation website

Hetfield's battles with addiction were laid bare in the band's 2004 documentary film Some Kind of Monster