The atmosphere was tense as residents confronted Amsterdam's mayor on a controversial plan to move legal prostitution from the city's historic red light district to a suburban "erotic centre".

In a meeting hall in the south of the city, hundreds of angry locals who don't want a "mega brothel" on their doorstep found themselves unexpectedly on the same side as sex workers who want to stay in their red neon booths.

In the middle of the row is Amsterdam mayor Femke Halsema, who is sticking to a plan that few people seem to like despite being branded a "brothel madame" by opponents.

"It's not possible," one mother said in tears at the meeting in the south of Amsterdam, near one of three sites that Halsema has proposed for the 100-room erotic centre.

One older resident wears two gold balloons saying "NO" around his neck, while others in this nation of cyclists carry small flashing red bike lights as a sign of protest.

Sex workers, meanwhile, insist they want to stay in the "Wallen" red light district, and that they are being scapegoated for complaints about crime, drunkenness and drug abuse in the area.

"The mayor says we are just a tourist attraction and people come and laugh at us," one sex worker who gave her name as Michelle told AFP after the meeting. "That's just not the case."

'Resistance' 

The issue has turned into a battle for the future of Amsterdam, as it tries to shed its "sin city" image and ease the impact of mass tourism, while still keeping its soul.

It could take several years before any erotic centre takes shape, with Amsterdam municipality aiming to decide on a location by the end of 2023.

"There will always be protests, there will always be resistance, whatever solution we choose," a visibly tired mayor Halsema told AFP with a sigh after the meeting.

In March, dozens of sex workers wearing masks and carrying banners saying "Save the Red Light" confronted the mayor at city hall, saying the plans would harm their livelihoods and were unsafe.

The mayor was also accused at the meeting of harming the Netherlands by driving away business.

The row even involved the European Medicines Agency (EMA), which has strongly opposed the fact that two of the proposed sites are near its new headquarters in south Amsterdam, where it moved after Brexit.

But organisations like the EMA "know what city they're based in", Halsema retorted.

The mayor said she was convinced that the erotic centre would not cause any danger and that sex workers would in fact be more secure.

Sex workers themselves dispute that.

"If you're already inside that's fine, but you also have to go out with your earnings," Michelle said.

She also argued that the 100 booths for sex workers in the erotic centre were far fewer than the 250 spots in the red light district.

But, with its spaces dedicated to rest, art, culture and "erotic" entertainment, the planned centre could be beneficial for some, so long as the aim is not to shut down the red light district altogether, she added.

'Witch hunt'

Amsterdam's red light district is only a "small part" of prostitution in the Dutch capital, says Alexander de Vos, a former sex worker who attended the meeting.

"There are also trans and gay" sex workers for whom there is "no place, and this centre offers them an option," he told AFP.

"But I don't support closing the red light district."

De Vos was one of the sex workers who protested in Amsterdam recently against the plans and also against increasingly restrictive measures in the Wallen.

Brothels must now close earlier at weekends, while Amsterdam also recently announced a ban on smoking cannabis -- which can be purchased at Amsterdam's equally famous coffee shops -- in the red light district.

Amsterdam also launched a recent "Stay Away" campaign aimed at young British men planning "wild" weekends in the city.

But opponents say the measures are a "witch hunt", and have argued for years that simply moving out prostitution would impact their livelihood without solving the problems of the crime-plagued neighbourhood.

The red light district is "full of signs about everything that's forbidden", said Michelle. "The problem is that no one gets fined. It would be a good start if the municipality would actually apply the existing rules."

Residents of the Wallen -- a centre for prostitution since the 16th century -- "know where they're living", she added.

Sex workers were also sceptical about the mayor's wider claims to be making Amsterdam more liveable for its residents, as the city grapples with over-tourism and a housing shortage.

"It's very safe here, very well organised, why fix something that isn't broken?" asked Michelle.

"It seems like it's a plan for gentrification."