Models in Singapore
Women pose with Abercrombie & Fitch models in Singapore's main shopping district. Reuters

(Reuters) Shirtless men clad in red sweatpants have been lining up for days in Singapore's prime shopping district, part of an advertising gimmick revealing not just muscle but also a gradual unpeeling of the city state's puritanical ways.

The feverish reception given the shirtless greeters by the Singapore public, both in real life and online, where it has gone viral in social media, signals how the notoriously conservative city-state has been loosening up in recent years, experts said.

On a recent evening, women stood with the men for pictures, touching them on the chest or receiving a friendly embrace. One even jumped up on a greeter's back.

The men, from the United States, Europe and Asia, are on a mission to drum up excitement for fashion retailer Abercrombie & Fitch's flagship store in Singapore, which opened on Thursday, using a campaign also employed overseas.

There's no way such advertisements that push the envelope slightly would have appeared about 30 years ago, said M. Thiyagarajan, a senior lecturer at Singapore Polytechnic's business school who specializes in advertising and public relations.

I think as a society we have moved to a different level. We are far more accepting of such things.

He cited the spread of the Internet, education and overseas travel as factors that have helped open minds in Singapore, which officially is still such a strict society that a ban on sales of chewing gum was renewed last year.

Local theatres have recently staged plays exploring traditionally controversial themes such as homosexuality and religion. Gay sex can still lead to a jail term of up to two years, although such laws are rarely enforced.

In October, a performance by French dancer Sylvie Guillem also contained some scenes of upper body female nudity.

However, conservatives in the city-state are still making their voices heard.

A letter to the editor in a local paper last month complained about naming an orchid after singer Elton John, asking if homosexuality was to be openly encouraged and endorsed by the government.

In September, the Advertising Standards Authority of Singapore told A&F to remove a giant billboard showing a naked male torso after some members of the public complained that it was too racy.

It is probably the response of a vocal minority, a storm in a teacup, who would use any occasion, however small, to raise the alarm, said Tan Ern Ser, an associate professor at the National University of Singapore's sociology department.

The shirtless greeters appear, for now, to be reaping more positive than negative attention.

I think it's a pretty effective way to publicize the brand leading up to its launch, and I like how it's an outdoor campaign which has taken its own life online, said Cathryn Neo, a recruitment consultant. And I do find them hot.

(Editing by Elaine Lies and Jonathan Thatcher)