Work by the Vatican has begun on showers and public toilets at parishes across Rome.

The upgrade of toilets which began November 17 was triggered by a homeless man, who initially refused a Polish bishop's invitation to dinner because he was filthy.

Pope Francis ordered the fitting of showers to public toilets around the Vatican, which will serve millions of pilgrims and visitors going to the Holy See every year.

The Pope's action comes ahead of U.N. World Toilet Day on November 19.

"Equality and dignity have a very concrete meaning in the lives of billions of people when it comes to sanitation," U.N. Special Rapporteurs Catarina de Albuquerque, Rashida Manjoo and Maud de Boer-Buquicchio said in a statement.

For the occasion of United Nations World Toilet Day, they said, "Women and girls in particular experience the indignity and risks of a lack of adequate sanitation in multiple ways."

The United Nations experts on water and sanitation noted that in many countries, social or cultural norms prevent girls and women from using the same sanitation facilities as male relatives.

U.N. Special Rapporteur on Violence Against Women, Manjoo said, "According to 2014 estimates, more than one billion people still practice open defecation and studies from very diverse countries reflect the risks women and girls face when doing so.

"Women and girls are disproportionately affected by harassment, assault and sexual violence when relying on public toilets or when forced to practice open defecation, largely due to the lack of access to a latrine at home or safe latrine facilities in the public sphere."

Back at the Vatican, Francis issued his order after learning of an encounter between a street dweller and Polish bishop Konrad Krajewski, the papal almoner, Vatican Radio reported.

Krajewski had finished hearing confession in the Church of the Holy Spirit when he took a walk along the Via della Conciliazione and bumped into a homeless man.

The man from Sardinia spoke with Krajewski, who is known as Father Konrad. The papal almoner is tasked to deliver charity to the poor.

"He told me that he was turning 50 that day and that he had been living on the street for 10 years," Krajewski said in an interview with Italian daily newspaper La Stampa on November 13.

The priest immediately invited the man to join him for dinner, but he declined, saying "Puzzo" (I Smell).

Undeterred, Archbishop Krajewski took the homeless man out for a meal anyway at a Chinese restaurant.

The man told the bishop  that staying clean in the area seemed to be more of a challenge compared to getting a meal for the hungry.

The priest got help from donors: a construction firm volunteered to work on the installation of showers in parishes which did not have such facilities.

Work began Monday on installing three showers a few meters from Casa Santa Marta, where the Pope resides. Aside from taking baths, people can also use it to wash their clothes.