Serial killer Ivan Milat has been diagnosed with cancer, according to reports from The Daily Telegraph and 7 News.

Milat, who is serving seven consecutive life sentences, was transferred from Goulburn supermax prison to the Prince of Wales Hospital in Sydney on Monday night, reportedly to undergo tests for organ failure related to his history of hunger strikes.

7 News is reporting that Milat is currently in the advanced stages of cancer. According to The Daily Telegraph, his family only just learned of the cancer diagnosis, initially understanding his treatment to be regarding stomach problems. Family members told the Daily Telegraph that Milat had lost more than 20kg in just two months.

While he was originally expected to return to Goulburn this week, 7 News is reporting that, in light of the diagnosis, he will no longer be heading back.

Image: AP