The Islamic Solidarity Games open in Indonesia this weekend following a chaotic run-up, with controversy over female athletes competing in sports bikinis adding to the turmoil.
Some nations demanded that all women cover up for the beach volleyball, track and field, and swimming events, but organisers have refused to axe the two-piece sporting outfits.
"If some countries do not want to use the bikini, that's fine, but if other countries want to, we will allow that," senior organising committee member Djoko Pramono told AFP.
"We agreed to apply international rules, including the dress code."
Thousands of athletes from 44 nations with Muslim populations will come together for the games, but only those ruled by Islamic governments opposed the bikini, Pramono said, adding they complained collectively.
He did not mention the countries which complained by name.
This year is the second time the games have been held, the first in Saudi Arabia, where not only were there no bikinis, but men and women competed on separate days and men were barred from watching women swim.
Some countries also asked the organisers to again run male and female events on separate days.
Pramono said he did not know which teams had decided to wear the bikinis.
Female players from Malaysia, Indonesia and Brunei have worn them at previous international competitions.
The event has faced a string of other problems, in the latest chapter of Indonesia's shambolic history of hosting of major sporting tournaments.
It is set to officially open Sunday and run until October 1 after months of delays and two changes of venue, now in Palembang city on Sumatra island.
Unpaid labourers shuttered the stadium in the original host city, Pekanbaru, with the governor embroiled in multiple corruption scandals unable to help.
It was moved to the capital, Jakarta, only to be shifted again to Palembang after Sumatran officials complained, giving organisers less than two months to move everything to the new venue.
Eyebrows have been raised over the Palembang complex, where parts of the ill-fated 2011 Southeast Asian Games took place.
Some facilities were not fully constructed as the 2011 event opened and scores of athletes suffered food poisoning there.
During that event, two football fans were crushed to death in a stampede at a venue in the capital as security guards were unable to control a massive crowd.
But Pramono was optimistic about the Islamic games, which includes archery, badminton and karate, and brings together nations from the Organisation of Islamic Cooperation.
"Everything is progressing, and I'm sure all 13 sports will be a success," he said.
The religious-based row is not the first to hit an international sporting event.
Last year, the International Judo Federation told Saudi Arabia's first woman to compete at the Olympics, Wojdan Shaherkani, that she could not compete in a Muslim headscarf.
A compromise was reached and she fought in a modified head covering at the London Games.