Australian Federal Police have apologised after leaving 230 grams of plastic explosive in an unclaimed suitcase at Sydney Airport.

The Newcastle Herald reports the explosive was discovered after the unclaimed bag was given to a woman as a replacement for her damaged bag.

The Australian Federal Police have left explosives at Sydney Airport. Credit:Tamara Dean

The explosives were left behind after a training exercise on August 14 but discovered on Tuesday after the woman took the unclaimed bag.

After finding the device, the woman immediately took it to Cessnock police.

