Individuals or groups are falsely posing as contact points for the sale of tickets for the papal mass, the news portal Channel News Asia (CNA) reported on Tuesday.
"Tickets for the papal mass are free, if available," CNA quoted the Archdiocese of Singapore as saying. "We urge the public to remain vigilant and not fall victim to these scams."
The only legitimate sources of information related to the papal visit are the archdiocese's website and the special website for the papal visit.
Pope Francis is travelling to Indonesia, Papua New Guinea, East Timor and Singapore in September.
The Pope will be in Singapore, the last stop on his trip, from 11 to 13 September.
Around 19 per cent of Singapore's approximately six million inhabitants are Christians, including 221,000 Catholics.