The London Olympics which open Friday mark the first time the Summer Games will be held during the Muslim fasting month of Ramadan since the 1980 Moscow Olympics.
During Ramadan, which began last weekend, Muslims are expected to abstain from food, drink and sex from dawn until sunset, when they break their fast with a meal known as Iftar.
But a senior member of the National Fatwa Council, Malaysia's top religious authority, said athletes can postpone their fast until after the Games as they are competing at an international event for the nation's honour.
"They are going to the Olympics to bring fame for the country. They can fast when they return to Malaysia," Mufti Harussani Zakaria, the top religious official for the Malaysian state of Perak, told AFP on Monday.
"The Quran says if you have a mission to complete, you can postpone the fasting but you must replace the number of days you did not fast."
Eleven out of the 30 Malaysian athletes going to London are Muslim.
One of Malaysia's top medal prospects, cyclist Azizulhasni Awang, who won silver at the 2009 track cycling world championships, is among the athletes who will put off fasting, Malaysian media reported this week.
Sieh Kok Chi, secretary of the Olympic Council of Malaysia, also said Olympic athletes should not fast while competing.
"It is a once in their lifetime chance to participate in the Olympics. They should opt out from fasting for one or two days so that they stand a chance of winning a medal," he told AFP.
Malaysia will compete in nine sports in London, with Muslims taking part in archery, cycling, shooting, sailing and track and field.
Shooter Nur Suryani Mohamad Taibi, who will compete in London despite being eight months pregnant, is excused from fasting since she is expecting, but said all Muslims should be excused from fasting during competition.
"Islam is lenient. It is not a religion that forces people. Actually when we go to London we are termed as travellers. Islam allows us to postpone our fasting," she said.
British tabloid The Daily Mail reported in 2006 that the London-based Islamic Human Rights Commission said the Olympics timing was insensitive while Turkey, Egypt and Morocco lobbied for it to be rescheduled.
The International Olympic Committee, however, declined the requests, saying the Games were a secular event.
Islamic authorities in countries such as Saudi Arabia, Egypt, the United Arab Emirates, Algeria, and Morocco have recently allowed their athletes to postpone their fasts despite disagreement from some Muslims.