Beyonce has canceled two arena dates and pushed back the start of her upcoming Australian tour citing an "unforeseen change in her international schedule."

The American pop singer's "I Am" Australian tour was slated to start Sept. 12 at the Brisbane Entertainment Centre, but will now begin Sept. 15 with a show at Melbourne's Rod Laver Arena, promoters Michael Coppel Presents said today (July 22).

For Brisbane concert-goers, her original opening show has been rescheduled for Sept. 20. However, the second concert originally booked for Sept. 13 has been canceled, meaning the potential loss of more than 10,000 ticket sales.

Sydney fans will miss the artist's third show on Sept. 20 at the 18,000-capacity Acer Arena, which has now been pulled from the itinerary.

Those who bought tickets for the two canceled shows will be refunded by Ticketek.

Industry observers reckon the singer redrew her Australian touring plans after getting a call-up to take part in the September 13 MTV Video Music Awards.

In other news, promoters MCP said this afternoon that Pink would resume her record-busting "Funhouse" Australian tour tonight as scheduled at the Brisbane Entertainment Centre. Pink had postponed Monday night's show due to a bout of laryngitis. The arena show marks the start of the second leg of Pink's three month, 58-date Australian run, which has sold well over 600,000 tickets.