A Chinese national was shot and wounded in an attack in Karachi on Wednesday, police said, two weeks after nine Chinese workers were killed when an explosion sent their bus over a ravine in the north of the country.

Wednesday's victim and another Chinese national were being driven to Karachi's industrial area when they were attacked, police deputy inspector general Javed Akbar Riaz said.

"Two men wearing face masks riding a motorcycle carried out the shooting," Riaz told Reuters, adding that the men were travelling without a police escort.

No one claimed responsibility for the attack.

Speaking in Beijing, Chinese foreign ministry spokesperson Zhao Lijian described the incident as "an isolated case".

"We have full confidence in the Pakistan side's protection of Chinese citizens and property in Pakistan," he told a regular news briefing.

China is a close ally and major investor in Pakistan, and various militants opposed to the Pakistani government have in the past attacked Chinese projects and citizens.

As many as 13 people, including nine Chinese nationals working on a dam project, were killed when their bus was hit by an explosion in Kohistan, northwest Pakistan, on July 14.

Pakistan initially blamed a mechanical failure but later said traces of explosives had been found and terrorism could not be ruled out. Chinese Premier Li Keqiang described it as a "terrorist attack" and urged his Pakistani counterpart to hold the culprits accountable.

Chinese investigators accompanied by Pakistani counterparts visited the site of the bus explosion on July 17.

The Chinese workers killed on the bus were employed at the Dasu hydroelectric project, part of the China-Pakistan Economic Corridor (CPEC), a $65 billion investment plan aiming to link western China to the southern Pakistani port of Gwadar.

CPEC, part of Beijing's massive Belt and Road Initiative, has brought thousands of Chinese workers and engineers to work in Pakistan over the last six years.

It was not clear if the Chinese national shot on Wednesday was linked to any CPEC project.