Australia's former conservative prime minister Scott Morrison has revealed he took medication for "debilitating" anxiety while in office, in a media interview published Friday.

Morrison, whose conservative coalition lost power in May 2022, told The Australian newspaper that the anxiety he experienced in office was "debilitating and agonising."

The 55-year-old evangelical Christian governed for four years managing crises such as the Covid-19 pandemic, and the widespread 2019-2020 Black Summer bushfires.

"I think it just built up," Morrison told the paper.

"It was a very stressful period," he said, citing long hours, the pandemic and difficult relations with China, which imposed trade barriers on major Australian exports during his term.

"You're flesh and blood and so it would start to impact you."

Morrison was prescribed medication for anxiety by a doctor in Canberra, the paper said, also citing excerpts from his new book to be released in May, "Plans for Your Good: A Prime Minister's Testimony of God's Faithfulness".

"My doctor was amazed I had lasted as long as I had before seeking help," Morrison wrote.

"Without this help, serious depression would have manifested."

Anxiety could have a profound personal impact, Morrison said.

"You dread the future and you can't get out of bed. It can shut you down mentally and physically. It robs you of your joy and can damage relationships. I know this from personal experience."

Morrison, an avid supporter of the fossil fuel industry, announced in January he was leaving politics.

As Australian leader, he notably angered France when he negotiated a deal behind closed doors to acquire US and British nuclear submarine technology, abruptly ditching a long-standing agreement with Paris.

And he secretly appointed himself to several ministerial roles during the Covid crisis, without informing his cabinet, the incumbents, or the public.