Zarin Havewala doesn't call herself a professional matchmaker, but her track record suggests otherwise.

"So far, 55 couples have found their partners through my efforts — 53 couples are already married, and two more couples are engaged to be married soon," says Ms Havewala, a Mumbai-based mother-of-two.

Ms Havewala is a Zoroastrian — or 'Parsi' (meaning 'Persian') as they're known in India — a member of an ancient monotheistic faith that pre-dates Islam and Christianity.

Zoroastrianism was the official religion of Persia, its birthplace, for more than a millennium, but today the community is a fraction of its former size, and that's raising serious concerns about the future of the faith.

Ms Havewala calls herself "a housewife who's involved in some social causes". ( Supplied )

"About seven years ago, it struck me very badly [that] a lot of our youngsters are getting married outside the community," Ms Havewala explains.

"I thought maybe they are not having enough avenues to know that there are other young Parsis available."

Unofficially, she now manages an international database of Zoroastrian bachelors and bachelorettes — an extensive list of names and numbers, careers and qualifications, ages and email addresses — that's shared with singles who are looking for love.

It started as an idea for Indian Parsis, but word quickly spread and soon Zoroastrians living everywhere, from Austin to Auckland and Iran to Oman, began contacting Ms Havewala for her coveted list.

"It's entirely word of mouth," she says.

"I don't advertise, I'm not on social media, but daily I get about three to four youngsters who send their bio data to me and I keep on sending them a long list of suitable matches."

Modern-day matchmaking

Sorry, this video has expired What is Zoroastrianism?

Back in 2015, Sydney-born Auzita Pourshasb was one of the names on Ms Havewala's list.

"When you're taught that you're a part of a diminishing community… you feel like you've got a sense of responsibility to meet a Zoroastrian and to help those numbers grow," says Ms Pourshasb, a 30-year-old HR advisor and member of the Australian Zoroastrian Association.

"It has definitely been challenging because already in the Sydney community you're faced with not a great number of bachelors to choose from, and the other thing is you grow up with them as though they're as close to you as family … so it'd feel weird to even see them as your partner."

According to the 2016 Census results there are fewer than 3,000 Zoroastrians currently living in Australia. The community is so small it makes up 0.01 per cent of the national population.

Auzita Pourshasb (right) expected to marry a Zoroastrian, but instead found love with a Christian, Nathan Secomb. ( ABC RN: Siobhan Hegarty )

Ms Pourshasb eventually met and fell in love with a Christian man. But before she met her current partner, she heard of Ms Havewala's database and decided to get in touch.

"She shared my details with the available bachelors and then shortly after I had people from India, Pakistan, England and Canada contact me," she recalls.

"I even had parents contact me saying, 'We're looking for a potential suitor for our son', and one family asked me for my time of birth and location of birth so they could match our horoscopes!"

Tinder for Zoroastrians

But Ms Havewala's dating database isn't the only online matchmaking resource for young Zoroastrians.

In 2016, Indian model and actor Viraf Patel launched the Parsi-only dating and social connectivity app, Aapro.

Zoroastrian Farhad Malegam says it's very similar to Tinder — "you swipe if you like someone" — except matches aren't limited to people in your area.

Farhad Malegam identifies as 'Parsi' and 'Zoroastrian' due to his ethnic and religious background. ( Supplied: Farhad Malegam )

"[If] I'm sitting here in Sydney, probably there's not too many people [nearby] who would use the app, but there would be someone in North America or New Zealand or maybe in India or Iran," explains Mr Malegam, a digital start-up entrepreneur and keen user of the app.

The 26-year-old says it's his preference to marry a member of the faith, but it's not a prerequisite. So far, he's yet to meet the one.

'We will eventually be extinct'

It's estimated there are 200,000 Zoroastrians worldwide with the majority (around 60,000) residing in India.

"Zoroastrians came to India about 200 years after the advent of Islam in Persia [because] there was a lot of oppression and religious conversion," Ms Havewala explains.

Committed to preserving the religion and its beliefs — which centre around the core tenets of 'good words, good thoughts, good deeds' — India's Parsis forbade converts from joining the faith.

Elsewhere in the world however, Zoroastrian communities do accept converts.

Known as the Faravahar, this symbol represents 'good thoughts, good words and good deeds' with its three wings. ( ABC RN: Siobhan Hegarty )

In Australia, Ms Pourshasb says conversions are occurring, but orthodox members of the community aren't happy about it.

"We definitely do know someone in the community who's doing all the conversions, [but] that particular situation is causing a bit of a divide," she says.

"If we don't allow converts into our community, we will be faced with diminishing number and our population will eventually be extinct."

For Ms Havewala, the declining Parsi population in India is particularly worrying.

"The way the numbers are going, within 50 years or a maximum 100 years, we just won't be there — I'm talking about Parsis in India," Ms Havewala says.

"Every year we get the statistics in which the births are, say, about 50, then the deaths would be 10-fold."

According to Mr Malegram, who moved from Mumbai to Sydney in 2015, Parsi protectionism is to blame.

"In India to protect that Iranian ancestry and the genome, they decided to prohibit any inter-faith marriages and prohibit other people from entering the faith," he points out.

"It kept the ethnic group alive for thousands of years, but in the process, it did compromise on the bigger picture, which is the faith itself."

Despite the Parsi population decrease, Mr Malegam says new temples around the world are welcoming new members into the fold.

He's hopeful that online technologies and database-wrangling matchmakers will not only help Zoroastrians like himself to find love, they'll bring new life to the faith.

"We should do what we can to let this ancient faith, that's almost 4,000 years old, survive and continue," he says.

"The fact that we are here today is because of a lot of our ancestors did not want to change, [but] it's high time that the community does, and I think this generation, my generation, is very excited."