In what is seen as a sign of increasing Islamisation in a country that is officially a secular state with Islam as its official religion, the northern state of Pahang has introduced heavier penalties on "cross-dressers" under an amended Syariah law, according to local news reports.

Malaysia’s state-run news agency Berama reported that those arrested under the new law could face a maximum of a year’s jail or be fined up to RM1,000 (£ 185) or both if convicted. Under civil law, non-Muslim transwomen are usually charged under section 21 of the Minor Offences Act and fined RM 25.

The amended law, which came into effect on Dec 1, 2013, will only apply to Muslim men or women found to be wearing clothes of the opposite gender.

Pahang Islamic Religious and Malay Customs Council (Muip) deputy president Datuk Seri Wan Abdul Wahid Wan Hassan was quoted in the New Straits Times as saying that the lack of stern punishment against mak nyahs (men dressed as women) and pengkid (women dressed as men) had resulted in a rise in immoral activities in the state.

“Previously, when it came to cross-dressing, Muip only detained and advised them to change their behaviour. However, such activities have become rampant, forcing the council to introduce a more severe punishment,” he added.

No reports of arrests had been made by the council since the amended law was introduced.

Other offences include khalwat (close proximity between unmarried opposite-sex couples), consuming alcohol and not fasting during Ramadan.

Women’s Aid Organisation executive director Ivy Josiah questioned the definition and existence of "cross-dressing" law.

"Modern attire is eclectic in nature and many women these days wear trousers and sport short hair. How do we even define what cross-dressing means? Cross-dressing is not about hurting other people or taking property from anyone. It’s a personal choice." She told the Times.

Syariah lawyer Nizam Bashir Abdul Kariem Bashir has also spoken out against the law as being unconstitutional and against the Pahang state department for acting beyond its rights in regulating attire.

The Quran doesn’t specifically address "cross dressing" although it urges its followers to dress modestly.

Nizam explained that there must be a concrete link between cross-dressing attire and immoral activities before one may justify such an action, and that laws should not based on vague probabilities.

He told Malaysia’s The Starnewspaper: “If you refer to the Quran, surah An-Nur verse 30 and 31, at best it only talks of modest attire and nothing more. Nevertheless, to be fair, the position does become more nuanced if Hadith (the Prophet’s sayings) are accounted for. When states propose to enact any Islamic law, they must first be able to characterise the legislation as conforming to Islamic law.

“If the Quran is accepted as the primary source of Islamic law, then state legislative assemblies are legislatively incompetent to enact laws regulating attire.”

Pahang has a population of 1.4 million of which 1 million are Muslims.

Each of the country’s 13 states enforces its own religious laws and moral guidelines governing Muslims ranging from interaction between unmarried couples – in public and in private – to strict dress codes to ban on alcohol consumption.