The chance to make new friends, a passive income and a weak rental market are among the reasons why people here offer their homes and rooms for short-term rentals even though the practice is illegal.

One such host on home-sharing website Airbnb told The Sunday Times that he started letting out his condominium unit at the end of last year as he found it increasingly difficult to find a long-term tenant.

The 56-year-old businessman, who asked to remain anonymous, said: "The rental market now is horrible. I started doing this to defray my mortgage and maintenance costs on the apartment."

To date he has hosted about 20 groups of visitors at his city-fringe condominium for about $150 per night. A four-star hotel in the same area could cost twice as much.

"Visitors to Singapore may not have the budget for luxury hotels and may not like hostels," said the businessman, whose guests include tourists and business travellers from countries like Britain, China and Malaysia.

"They like staying in a condo because it's almost like a hotel suite. They can even cook and do their laundry."

The host soon discovered other perks. "When I have time, I take my guests out and become their unofficial tour guide," he said. "I point out where the hawker centres are, what are the good dishes to eat - stuff which only a local would know."

An Airbnb "superhost" - an experienced host who has received good reviews - said he occasionally gets Singaporean guests over the weekend.

"They want to buy a place here and get a feel of the neighbourhood," said the 33-year-old, who lets out two rooms in his Buona Vista condominium apartment.

But most of his guests are foreign professionals and research students who are here for a few months.

"I like getting to know people from all over the world," said the tech start-up founder, who has hosted more than 40 guests from countries including Finland and Germany since June last year.

"When I travel, they even help me water my plants. We add each other on Facebook and some of them have become business contacts."

Another host, a 30-year-old nail artist and freelance travel planner, also said some of her guests have become good friends.

"I visited them in their countries and they welcomed me to their place without any charge," said the host, who leases out a spare room in her Balestier condominium.

But things are not always peachy.

"Some treat me like a hotel boy and want me to do everything for them," said the start-up founder.

The businessman host has had guests steal two towels from his apartment. Some others do not clean up after cooking in the kitchen, or leave the air-conditioner on when they go out.

"It's very time consuming. We have to be there to open the door for guests, clean up the house and get calls in the middle of the night from those who lock themselves out of the room," he said.

"I don't intend to do this for too long."

Yeo Sam Jo