In the first-ever arrest of its kind inside the Vatican, a former archbishop accused of paying for sex with children, while he was serving as a Vatican ambassador in the Dominican Republic was arrested on Tuesday.

A statement issued by the Vatican said that Jozef Wesolowski has been placed under house arrest awaiting a criminal trial.

The arrest comes after Pope Francis insisted, "that such a grave and delicate case has to be handled without delay, with the just and necessary rigour."

Wesolowski was earlier detained in the Vatican prison but later granted house arrest in a Vatican apartment for medical reasons.

Victims called for his arrest over fears that he might attempt fleeing from the trial.

Wesolowski, 66, was recalled to Rome last year and defrocked by a Vatican tribunal in June after Dominican media pressed paedophilia charges on him while he was serving as a diplomat in Santo Domingo.

He is the most prominent church member to be arrested since the arrest of the pope's former personal butler since 2006, Paolo Gabriele in 2012.

If found guilty, Wesolowski could serve up to 12 years in jail in the first trial for sexual abuse to be held inside the Vatican City.

Meanwhile, authorities in the Dominican Republic are investigating reports that Wesolowski paid young boys to perform sexual acts.

Pope Francis is the first non-European pope in 1,300 years and he has pressed on a zero tolerance policy against sexual offenders calling the abuse, an "ugly crime" and linking similarities with "a Satanic Mass".