Australian Treasurer Peter Costello under increased protection?

Australian Treasurer Peter Costello - in the run up to a well contested election, appears to be under increased protection by the Australian Federal Police.
An itsNbits staff member driving past noticed the first AFP car, something not normally seen at Mr Costello’s Malvern headquarters.
It is unknown if Mr Costello was in the building, but if he was, it could explain the increased Federal Police presence - however the absence of visible protection at any other time leads itsNbits to ponder whether the protection level has been recently increased. It is also possible that an event or threat has has occurred that has required an upgrade to security levels for Mr Costello who is the Treasurer of Australia.
Whilst itsNbits was watching, two Federal Police appeared to do a walking perimeter check including nearby streets. A third officer appeared to be on guard just inside the front door.
Minutes later a second Australian Federal Police car turned up, and officers were seen to discuss something for a while before the second car left the scene.

Mr Costello is expected to succeed current Prime Minister John Howard in the event the Liberal Party wins the November 24 Election as Mr Howard has announced he will not run the full term. The election is contested by Kevin Rudd, the new leader of the Labour Party.
The election is set to be a hard won battle for the victor.
On top of the potential for the security to be related to the election lead up, Australian hit comedy team The Chasers are well known to pay surprise visits to well known people as part of the comedy television program.
Recent Chaser stunts include confronting the prime minister whilst on his regular morning walk - with a chainsaw, and managing to bypass the tight security at the 2007 APEC summit in Sydney whilst dressed as Osama Bin Laden.