Unmarried Muslims are being told it would be "un-Islamic" to celebrate Valentine's Day.

The Federation of Islamic Associations says celebrating the day of love and affection often involves activities that are intimate and sexual by nature, and it goes against the teachings of Islam for singles and unmarried people to engage in such activities outside of marriage.

"We do not want that kind of atmosphere, because that is totally un-Islamic and not acceptable," said Javed Khan, the federation's senior vice-president.

On Thursday, the Dumai Chapter of the Indonesian Ulema Council declared it to be "haram", or forbidden, for Muslims to celebrate the day named after one or more early Christian martyrs named Valentine, established by Pope Gelasius I in 500AD.

Council chairman Rozai Akbhar told the Jakarta Post Valentine's Day had originated as a "holiday for non-Muslims" in Europe, and it was therefore forbidden for Muslims to celebrate it.

Mr Akbhar said celebrating Valentine's Day went against Islamic teachings because it was akin to encouraging young people to build relationships outside marriage.

Concerns that it would become part of the Islamic culture was one of the main reasons for banning Muslims from celebrating it, he said.

Several Malaysian states are also planning "crackdowns" on immoral acts by Muslims on the day as part of a campaign to promote a "sin-free lifestyle", an AFP report said.

Authorities in Penang, Kedah, Kelantan and Selangor are planning to carry out "immorality checks" at hotels, parks and beaches on Monday. The head of the youth wing of the Islamic party PAS, Nasarudin Hasan Tantawi, said "spots" used by lovers had been identified and religious officials and party members would be deployed to stop sinful acts "like casual sex".

Mr Khan said the New Zealand federation's position was "not as extreme" as those of Islamic groups in Malaysia or Indonesia.

"Valentine's Day is a day that can strengthen the relationship between couples who are married, and that's all right in our view," he said.

"But celebrating the day does not give single Muslims the licence to be doing the same things that married people do."

Mr Khan, 62, said he used to celebrate Valentine's Day with his wife in their younger days.

However, two unmarried Muslim women the Weekend Herald spoke to in Auckland said they would be celebrating the day with their beaus despite the warning from their religious leaders.

"I don't think having dinner with someone you love on the day meant to celebrate love is sinful at all," said one, a flight attendant from Dubai.

Another, a 23-year-old Muslim student originally from Malaysia, said her South African-born boyfriend had already booked a table for a "romantic dinner" on Monday night.

Both women requested anonymity as they feared they could incur the wrath of disapproving Muslims because of their views.

Two Valentine's Day celebrations will be observed next week.

Valentine's Day falls on February 14, but the 15th day of the lunar calendar or lantern festival, which falls on February 17, is widely regarded as the Chinese Valentine's Day.

Chinese Valentine's Day, or Yuan Xiao, also marks the end of the Chinese New Year celebrations.