They claimed that, based on the Chinese lunar calendar, the date should be on May 31.
One caller, Madam Lau, said the norm was to mark the birth, enlightenment and death of Buddha on the full moon of the 15th day, in the fourth month of the lunar calendar.
May 1 fell on the 15th day in the third month of the lunar calendar, she said.
When the NST contacted the Malaysian Buddhist Associationís (MBA) headquarters in Penang for clarification, its secretary-general Lim Then Pong said the confusion was due to the occurrences of two full moons in May.
"It is correct that, as a norm, Wesak Day is celebrated on the 15th day in the fourth month of the lunar calendar every year.
"However, May 31, which is a full moon, is also the correct date for the celebration.
"This is because there is not one but two full moons occurring on May 1 and May 31."
Lim said the MBA had recommended to the government to gazette May 1 as a public holiday as it conformed with a resolution on the matter passed by the World Buddhists Conference in 1950 in Sri Lanka.
"This year, Malaysian Buddhists can celebrate Wesak Day either on the first day or the last day of May, or even both." He said the association would not interfere with Buddhist temples wanting to celebrate the event on May 31.