A total of 17,975 vehicles were seized and 874 drivers were detained in Shenzhen, South China's Guangdong Province as of March 31, only 10 days after police began a new campaign to ban unregistered or illegally piloted motorcycles and tricycles, an official with the city's traffic police department told the Global Times on Monday.

About 670 people were detained for driving without licenses, and 196 were detained for "disturbing order in public places" by carrying passengers for money, Liu Ming of the information office of Shenzhen's traffic police told the Global Times.

The campaign, which aims to prevent traffic accidents involving motorcycles and tricycles and to ensure fair competition in the transport industry, has made a splash online, as some delivery companies have complained they cannot operate until the traffic police are off duty.

The move even triggered the resignation of about 1,000 couriers, who feared they would be detained or fined by their company for failing to complete their workloads.

In Shenzhen, only 13,000 electronic bicycles are registered, or regarded as "legal," while about 3.6 million packages are expected to be delivered by electric motorbikes in the city per day, thepaper.cn said.

"The ban has hugely influenced our business," a manager surnamed Yan of YTO Express in Shenzhen, was quoted by the Chinese Business View as saying on Monday.

She explained that the daily amount of parcels received by her office dropped from 80,000 to 10,000 on average.

Since couriers primarily use electric tricycles, they now have to go out at 5 am to both collect and deliver parcels, which directly resulted in the sales drop, Yan said.

At least 1,200 vehicles from four major delivery companies in Shenzhen were seized, while 50 couriers were detained in the campaign, news site thepaper.cn reported Friday.

Most of the drivers have been released after being detained for three to five days, Liu said.