Most of the criticism has focused on his bloody anti-drug campaign, which has left thousands dead, alarmed Western governments and rights groups and prompted two complaints of mass murder before the International Criminal Court.

“At present in the Philippines the human rights abuses are just increasing and it’s a reign of terror and tyranny,” Fox told reporters after arriving at Melbourne airport on Sunday.

During a farewell news conference in a Catholic school before leaving for the Manila airport with a convoy of supporters, the 71-year-old Fox called on Filipinos to speak up and help the marginalised fight to gain land, houses and jobs.

“The big challenge now is not to lose hope, to know that if we all move together, we can bring about change,” Fox said.

“Pope Francis said that if you’re a Christian and there’s massive human rights violations … you should take action, make noise. Where the oppressed are, the church people should be there, not only always talking but with them and hopefully more vocal,” she said.

Fox said that Duterte’s anti-drug crackdown was “horribly barbaric” and she vowed to return to the country if allowed to resume her 27 years of missionary work for the poor.

“I know a lot of mothers, wives who have lost someone. You have no right to take a life just like that without justice,” Fox said.

Philippines President Duterte is investigating a 71-year-old Australian nun for ‘disorderly conduct’

Dozens of activists, labourers, priests, nuns and tribal people, some in tears, thanked Fox by celebrating a Mass in her honour before sending her off.

A lawyers group backing Fox, the National Union of Peoples’ Lawyers, said that by persecuting a frail and low-key missionary, Duterte has turned her into an “overnight rock star”.

Known for being soft-spoken, Fox is a coordinator of a Roman Catholic order of nuns and has worked for the poor in the Philippines.

She promotes human rights and the welfare of workers, farmers and ethnic groups and has spoken against Duterte and his government, which has also been criticised for stifling dissent.

She recalled in Melbourne that after she had spoken publicly in support for Coca-Cola workers seeking benefits in the Philippines, their picket was “broken up brutally, 10 of them were arrested and were five days in jail and not charged”.

“And so they were having a press conference and I did say to them, when they wanted me to speak, that the teachings of the Catholic Church clearly say you have a right to assembly, you have a right to unionise, you have a right to regular work. Now that, in the deportation order, was anti-government. One of the commentators said that now the social teachings of the Catholic Church are anti-government,” she said.

The immigration bureau said Fox violated her missionary visa by venturing far beyond her community in suburban Quezon City in metropolitan Manila and interfered in domestic politics by joining protests and news conferences that tackled “political and human rights issues against the government”.

Fox’s lawyers said she joined the marginalised as part of her missionary work and called the Duterte administration’s actions “political persecution”.

They expressed fears that the move to evict Fox could undermine the crucial civic and religious work of foreign missionaries in the country.

Aside from Fox, the government has separately blocked a critical Italian politician, Giacomo Filibeck, and another Australian, Gill Hale Boehringer, from entering the Philippines this year.

“The law is clear: The entry and admission of an alien is a matter of privilege, and not a right,” Bureau of Immigration spokeswoman Dana Sandoval said Saturday.