"I'm into religion, science and politics. Soccer, table tennis and swimming. Spending time with family," it starts.

But these are not your normal call-outs for a life partner.

"I have one wife and three children. My wife also greatly supports this lifestyle and is wanting a co-wife to be a part of our family," it continues.

The profile is just one of thousands on a match-making website for Muslim men and women looking for a second spouse. And it is rapidly gaining traction in Australia, its British founder says.

Azad Chaiwala has stirred controversy in Britain with his outspoken promotion of his website Secondwife.com. Since the age of 12 he desired to have multiple wives.

Polygamy is illegal in Australia yet Chaiwala believes a growing number of Muslims are seeking second marriages in religious ceremonies. He said the "social taboo" is fading away.

Fairfax Media found about 180 male users and 12 female users on the website who publicly list their location as Australia. Mr Chaiwala claimed the number of Australian users is as high as 750.

"A lot of Muslims give their cultural background precedence instead of looking at what religion says," he said. "There is a lot of stigma now against Muslims so they're being stupidly cautious."

The top of the site carries a line from the Koran: "then marry women of your choice, two or three, or four but if you fear that you shall not be able to deal justly, then only one".

He said a man is permitted to have up to four wives as long as he can afford it and treats them equally.

However Joumanah El Matrah, executive director of the Australian Muslim Women's Centre for Human Rights, said such interpretations were antiquated and demeaning.

"It's quite an underground practice in Australia," she said. "It's frowned upon because Muslims are of the view that you can't treat two women equally.

"Women and children fare very badly in polygynous set-ups. There tends to be a lot of suffering and loneliness. The limited evidence we have is that there is an increased risk of domestic violence."

She said the directive in the Koran was written in an era when women needed marriage for rights and support, whereas now they don't.

Keysar Trad, president of the Australian Federation of Islamic Councils, was raised in a polygamous Lebanese family and has sought a second wife for decades.

His wife of 30 years has previously voiced her support, saying she would rather he have a halal relationship with a second woman than an affair.

Other women on Secondwife.com say they're looking for a companion "sister wife" or someone who can provide the children or intimacy they can't.

"My wife is a saint, she's one of the best women out there but I think it's human nature, God put this drive very strongly inside males so that we can be providers and supporters for more than one woman," Mr Trad said.

He argued most men are not monogamous so polygamy means the "other woman" is given rights and equality rather than being simply a mistress.

Ms El Matrah labelled this idea "absolute nonsense from an Islamic perspective".

Buoyed by the success of his website, Mr Chaiwala set up another site, Polygamy.com, for non-Muslims.

Polygamy has been common in about 800 of 1000 societies, the University of Wisconsin found in an oft-cited 1998 study. Just 186 are monogamous.

Some indigenous tribes in Arnhem Land support the practice. Famous polygamists have included South African president Jacob Zuma and Australian actor Jack Thompson.

Dr Linda Kirkman, a sex and relationships researcher who has examined polyamory among middle-aged Australians, said it was wrong to assume women are treated badly in multi-partner relationships.

"There are women who choose this kind of marriage and it works really well for them," she said. "It's about having choice and within that choice making sure the behaviour is respectful."

Successive federal attorneys-general have ruled out changing bigamy laws.