In the run-up to Pope Francis' visit to Georgia, the Vatican spokesman had said the Orthodox Patriarchate would send a delegation to the Mass in a Tbilisi sports stadium "in a sign of the rapport between the two churches" - suggesting that the chill that had clouded the 1999 visit of Saint John Paul II to Georgia had warmed slightly.

But Orthodox patriarchate spokeswoman Nato Asatiani said on Saturday that the delegation had stayed away "by mutual agreement".

The patriarchate updated a previous statement on its website saying that "as long as there are dogmatic differences between our churches, Orthodox believers will not participate in their prayers".

The update apparently came after Pope Francis' arrival on Friday in Tbilisi was met with protests of hardline Orthodox members opposed to any ecumenical initiatives by their church.

"It's typical proselytising," said Father David Klividze, who was among about 100 people protesting outside the Meskhi stadium from the hardline Union of Orthodox Parents.

"Can you imagine how it would be if a Sunni preacher came to Shiite Iran and conducted prayers in a stadium or somewhere else? Such a thing could not be. Therefore, we are speaking against this."

Vatican spokesman Greg Burke said the Vatican accepted the Orthodox decision, which he said had been conveyed to the papal delegation on Friday night. Orthodox law did not allow for the participation of the delegation, he said.

Pope Francis had been scheduled to personally greet the delegation at the end of the Mass. Instead, Francis thanked "those Orthodox faithful" who were present.

Organisers had said they expected the Meskhi sports stadium, capacity 27,000, to be full for the Mass, but only a few thousand people took their seats in the stands by the time Francis entered on his popemobile and began the celebration.

There was no explanation for the low turnout of Catholic faithful on the brilliantly sunny day.

Georgia is overwhelmingly Orthodox, with less than 3% of the population - or about 112,000 people - Catholic, according to Vatican statistics.

In his homily, Pope Francis urged his faithful to find consolation in God and not be "saddened by the lack of harmony around us".

"It is when we are united, in communion, that God's consolation works in us," he said.

Pope Francis had received a surprisingly warm welcome from the Orthodox leader upon his arrival on Friday for the three-day visit that also includes a stop in Muslim-majority Azerbaijan.

Patriarch Ilia welcomed Pope Francis as my "dear brother" and toasted him saying: "May the Lord bless the Catholic Church of Rome."

It was a different tone compared to the chill that characterised John Paul II's 1999 visit, when Ilia greeted him only as a head of state, not a religious leader.

Other than Georgian president Giorgi Margvelashvili, there were no prominent Georgian politicians on hand for the Mass. That suggested that with parliamentary elections planned for next week, politicians might have been reluctant to alienate any hardline Orthodox voters with their presence.