A dock workers' strike at Hong Kong's commercial port was dealt a blow on Thursday as billionaire Li Ka-shing hired new workers to end the four-week-old walk out.

Kwai Tsing container terminals, which are owned by Li's Hongkong International Terminals Ltd., are operating at about 90 capacity, according to a company statement. The new hires, and some strikers who returned to work, have helped boost efficiency at the dock, cutting ship waiting time to 20-25 hours, down from nearly 60 hours at the start of the strike on March 28.

Hongkong International lost a considerable amount of its usual business during the strike. At least 100 vessels decided to skip Hongkong International's port in favor of nearby ports.

Despite the new hires, more than 100 strikers remain camped out in front of the Cheung Kong Center building, in the city's central business district, in defiance of Li's demands that they leave.

On Wednesday, about 20 workers managed to evade Cheung Kong building security by dressing in business suits and headed straight up to the seventh floor into corporate offices. They unfurled banners, shouted slogans and denounced Li as "a businessman with no conscience," according to South China Morning Post. The sit-in lasted for about 20 minutes before the protesters were forced to leave the premises.

Contract workers were offered a pay raise of seven percent by their employers, but the workers have demanded an increase of about 20 percent, citing higher living costs and record home prices. Government mediators have been called in to help the two sides narrow their differences.