Hong Kong’s housing market has shown little sign of cooling after years of consistent price increases. In response, the government is now considering a controversial measure.

Property in the semi-autonomous region of China has long ranked among the world’s most expensive due to inadequate land supply, robust speculation, demand from mainland Chinese buyers and years of enticingly low interest rates. Although many responses have been considered, the city’s government is now weighing a tax on vacant apartments.

That has developers crying foul and analysts questioning its effectiveness.

Such a tax is seen as a way to increase supply by nudging developers to unload stock rather than wait for prices to go higher. It would, the thinking goes, help address a social divide of property haves and have nots.

Hong Kong wouldn’t be the first to implement such a scheme — it would follow cities such as Singapore and Vancouver —but experts expressed doubt about whether such a levy by itself is enough to do the trick in Hong Kong. Instead, they said, the government measure would be just as much about politics as property.

“I see this policy as a demonstration that the government is doing something to remedy the situation (but) without much real impact,” Mathew Wong, a politics professor at the University of Hong Kong, told CNBC.

Wong said that slipping popularity ratings for top local official Chief Executive Carrie Lam, who marks one year in office on July 1, could be a factor in the announcement expected by the end of June.

Her support rating as tracked in University of Hong Kong polling stood at 54.3 earlier this month, down from 63.6 shortly after taking office.

Developers feel scapegoated and oppose the move, describing themselves as “puzzled” over the government’s thinking.

“Such a tax cannot dampen the price escalation that is the combined result of a persistent shortage of land supply and an abundant liquidity in an ultra-low interest rate environment,” the Real Estate Developers Association of Hong Kong said in a statement.

Packed onto small, hilly islands and a mountainous peninsula bordering southern China’s Guangdong province, many of Hong Kong’s approximately 7.4 million people are increasingly fed up with the world’s least affordable housing market.

A public opinion survey released in May by local non-profit think tank Our Hong Kong Foundation showed 77.7 percent of respondents were dissatisfied with crowded conditions.

Denis Ma, head of research in Hong Kong for real estate and investment management company JLL, said frustration is acute among the younger generation.

With apartments of 200 square feet going for the equivalent of $3 million, they “feel they can’t get on the housing ladder,” Ma said.

Hong Kong has in the past increased land supply through reclamation and opening up farm land. The government acknowledges more is needed. A land task force has even floated closing a golf course to build as many as 13,200 new apartments.

One reason analysts doubt a vacancy tax would have a major impact in Hong Kong is that there were only about 9,000 new-but-vacant apartments as of the end of 2017. The figure could go substantially higher if apartments coming onto the market in the next two to three years are counted.

Analysts said the impact could be larger over the longer term if the levy is high and if it is also applied to vacant used apartments, of which there are an estimated 30,000.

Still, a potentially bigger long-term factor for the property market is rising interest rates.

“It should slow the market down,” said Ma, though he cautioned that could take at least two years to be felt.

Hong Kong has close monetary policy ties to the United States because the local Hong Kong dollar is linked to the U.S. dollar. The U.S. Federal Reserve’s current trajectory of monetary tightening should, therefore, be reflected in Hong Kong’s economy.

Against that background, what form a vacancy tax will take remains a big question and any proposal needs approval by the local legislature.

Ultimately, the influence of developers looms large.

“I don’t think the government is willing to risk upsetting them,” said Wong.