BEIJING — Factory workers across China are staging sit-ins demanding unpaid wages for “blood and sweat.” Taxi drivers are surrounding government offices to call for better treatment. Construction workers are threatening to jump from buildings if they don’t get paid.

With economic growth in China weakening to its slowest pace in nearly three decades, thousands of Chinese workers are holding small-scale protests and strikes to fight efforts by businesses to withhold compensation and cut hours. The authorities have responded with a sustained campaign to rein in the protests, and most recently detained several prominent activists in the southern city of Shenzhen late last month.

Such protests are a glaring example of the challenges the sharp economic slowdown poses to China’s top leader, Xi Jinping, who has aggressively promoted the “Chinese dream,” his signature vision of greater wealth and a fairer society.

As Chinese families gather this week to celebrate the Lunar New Year, the most important holiday of the year in China, many workers say they are struggling to pay basic expenses like food and rent.

As economic forecasts have turned more sober, Mr. Xi has sought to defuse tensions by urging companies to pay salaries for low-income workers on time. The State Council, China’s cabinet, says it wants to eliminate wage arrears by next year.

Labor protests in China are common, and to avoid protracted conflicts, local officials often put pressure on businesses to settle disputes. But companies may be more unwilling — or unable — to do so now as they struggle to find money.

Mr. Xi has expanded the party’s oversight of the All-China Federation of Trade Unions, the party-controlled organ that is supposed to mediate disputes for its more than 300 million members but often sides with management. He has also dismantled nonprofit labor advocacy groups, which in the past provided advice to workers and helped with collective bargaining.

In a crackdown in Shenzhen in late January, the authorities detained five veteran labor rights advocates and accused them of “disturbing public order,” a vague charge the party often uses against its critics.

Now, with no independent unions, courts or news outlets to turn to, some workers are resorting to extreme measures to settle disputes.

Wang Xiao, 33, a construction worker, grew tired of lobbying his bosses for more than $2,000 in unpaid wages for a project in the eastern province of Shandong. So last week he turned to social media, threatening to jump off the headquarters of the company overseeing the project.

“If I get to the roof of the building and make a scene, then the money will be given to me more quickly,” he said in an interview. (Mr. Wang did not carry out his threat.)