Cardinal George Pell is Pope Francis' chief financial adviser and Australia's most senior Catholic.

He is the highest-ranking Vatican official to ever be charged in the church's long-running sexual abuse scandal.

Two men, now in their 40s, said that Pell touched them inappropriately at a swimming pool in the late 1970s, when Pell was a senior priest in Melbourne.

Pell said he would return to Australia to fight the charges.

Victoria state Police Deputy Commissioner Shane Patton said police have summonsed Pell to appear in an Australian court to face multiple charges of "historical sexual assault offences," meaning offences that generally occurred some time ago.

Patton said there are multiple complainants against Pell, but gave no other details on the allegations against the cardinal. Pell was ordered to appear in Melbourne Magistrates Court on July 18.