Sydney Airport defended its decision to rescreen passengers after a security device lost power yesterday afternoon. Virgin Blue, QantasLink and Tiger Airways flights were delayed until this morning as a result of a power failure that caused a security breach shortly after 4pm at Terminal 2 yesterday.

"You can't cut corners on security. Security and safety are our most important priorities at the airport, and you just have to follow that process," Rod Gilmour, General Manager of Corporate Affairs said.

He said they are still investigating what caused a loss of power to one of the security screens.

Yesterday, Sydney Airport had to clear the area and rescreen all passengers after walk-through security screening device had lost power, resulting in 16 passengers passing through without being properly screened.

As of today, extra flights have been scheduled to fly from Sydney Airport in a bid to clear several thousand passengers who were stranded.