Australian nun Patricia Fox has called on the Philippines government not to arrest or forcibly deport her pending a new appeal to the nation's Department of Justice alleging unfair treatment by immigration officials.
However, supporters fear the 71-year-old will be arrested in coming days.
A deadline set for her to leave has either already expired or will do so on May 25, depending on how the wording of the deportation order is construed.
Sister Fox, from the Sisters of Our Lady of Sion, was arrested on April 16 and detained for 22 hours for purportedly being involved in partisan political protests.
Get in front of tomorrow's news for FREE
Journalism for the curious Australian across politics, business, culture and opinion.
READ NOWOn April 23, her missionary visa was downgraded to a temporary visitor's visa and she was ordered to leave the country within 30 days.
Sister Fox told AAP that the Australian Embassy in the Philippines intervened on her behalf, requesting the return of her confiscated passport "but they have not been successful so far".
"They are still holding my passport, which they will not give up."
She also said a petition in Australia asking that she not be deported was being presented to the Embassy of the Philippines in Canberra.
The action against Sister Fox, who has been a missionary in the Philippines since 1990, comes amid a wider crackdown on critics of incumbent President Rodrigo Duterte.
On May 23, the Bureau of Immigration denied her 'motion for reconsideration'.
However, Catholic Church spokesperson Nadja de Vera has issued a statement confirming that Sister Fox intends to appeal to the Secretary of the Department of Justice alleging her case was not properly reconsidered.
"Sister Pat has the right to be accorded due process and equal protection of the law," de Vera said.
"She thus expects that the Bureau of Immigration would also follow the rule of law and their own procedures, and will not arrest or forcibly deport her, to give her the opportunity to appeal."
The Church said Sister Fox's case has far-reaching implications for other foreigners living in the Philippines, particularly missionaries working in "solidarity" with the poor.
Sister Fox has stressed that her joining protest rallies was solely aimed at protecting the underprivileged in society and did not constitute "political activity" as alleged.
The Catholic Church maintains that such involvement is protected by constitutional guarantees of freedom of speech and assembly to which foreigners are equally entitled.
Sister Fox told AAP that she has been receiving public backing from Protestant organisations as well as representatives of small-scale farmers and the urban poor.