The organisers had expected 65,000 people at the Vienna concert, with tickets for standing places priced between 63 and 212 euros, and seats costing up to 518 euros. London was expected to be cheaper.

Kindel said all those who had already bought tickets would be refunded. Organisers said they could not say how many tickets had been sold, but one Vienna agent said he alone had sold hundreds.

Celebrity website TMZ.com had reported Thursday that Natalie Cole was the latest announced star to distance herself from the event, quoting her representative as saying Cole was set to attend an event with the Dalai Lama around the same time in Memphis, Tennessee.

Browne's representatives revealed Tuesday that he would not attend the concert because he needs special court permission to leave the country following his conviction for assaulting his former girlfriend Rihanna earlier this year.

Blige backed away from appearing at the tribute concert due to a concert at the same time in Madrid.

Organisers had claimed that Michael Jackson's children and his mother, Katherine, were planning to attend the event, but reports in the US said that Katherine Jackson and other family members objected to the concert and would not attend.

Michael Jackson died June 25 at the age of 50 from an overdose of a powerful anaesthetic.