Kylie Minogue was hailed as the nation's most successful performer when she broke rock band AC/DC's record of six shows at the Sydney Entertainment Centre with February's announcement of a seventh concert.

After her sell-out national tour began in Brisbane on April 14, an eighth Sydney concert was announced.

The event sold out within two hours this morning, the Frontier Touring Company said.

Tickets for a ninth show, to be held on May 15, went on sale at midday today.

The announcement follows the pop singer's release of her own lingerie line yesterday and performances at three sold out Sydney concerts this week.

Kylie's national tour now comprises 22 shows with a combined audience of more than 200,000