Catholic churches in Cuba have begun rationing Communion wafers as the country's deepening energy crisis disrupts production, priests have told AFP.

The wafers, used during Mass to symbolise the body of Jesus Christ, are produced at a Carmelite monastery in Havana, but extended electricity outages have now severely limited manufacturing capacity.

Several priests said on Sunday that church authorities had instructed parishes to conserve supplies.

Communion wafers are made from a mixture of flour and water pressed into thin discs, which are distributed to worshippers during Mass.

Like much of Cuba, the monastery has been affected by prolonged power cuts, which have intensified amid fuel shortages. According to AFP, the situation has been worsened by a five-month-old US oil blockade.

In recent weeks, some areas of the island have experienced blackouts lasting more than 24 hours, affecting daily life for millions of people.

George Payano, a 35-year-old Dominican priest, said the nuns responsible for producing the wafers were often able to operate the presses for only a limited period each day.

"That means lower production, and as they (the nuns) told the priests and bishops, you have to ration them a bit so that there are enough for all," he said.

Despite the shortages, worshippers attending Mass on Sunday were still able to receive Communion. However, many expressed concern about the possibility of further restrictions if the energy crisis continues.

After leaving the church and finding another power outage in the neighbourhood, parishioners said they remained committed to their faith.

"People who don't receive communion can do so spiritually, but let's hope it doesn't come to that," said 70-year-old pensioner Mariela Shuman.