Tourists who weigh more than 100kg will no longer be able to ride on donkeys on the island of Santorini in Greece, after international pressure from activists.

The Greek Ministry of Rural Development and Food has stated that it will be illegal for owners to burden animals with any load exceeding 100kg or one fifth of their weight.

Tourists were not directly mentioned in the legislation but the regulation has been interpreted as a ban on overweight holidaymakers riding the creatures, reported British newspaper The Guardian.

The paper reported that the measure is part of a revived code of conduct aimed at improving the welfare of all donkeys, horses and mules.

According to CNN, the guidelines were circulated to island regions after the authorities received complaints over the poor living conditions of the domestic animals.

Donkeys are used to transport tourists up steep slopes from Santorini's shore to the island's main town.

But animal activists have said that the donkeys are forced to carry more and more tourists who are obese, leaving them with spinal injuries and open wounds from ill-fitting saddles.

The Help the Santorini Donkeys group had in July called for weight restrictions on those riding donkeys in the island.

A spokesman for the group had said then that locals were starting to use cross-bred mules to ferry tourists as donkeys were not strong enough to do so.

In a Facebook post on Friday night (Oct 12), the group said that animal welfare groups will be "watching like hawks" to make sure that the authorities keep their promise to improve animal welfare.