Immigration officers arrested 18 illegal workers and four employers in citywide enforcement actions on November 14 and 15.
Four Mainlanders were arrested for breaching their conditions of stay by being involved in parallel goods trading on Po Wan Road, Sheung Shui.
Fourteen illegal workers and four employers were arrested in raids on a construction site, a guesthouse, residential buildings, restaurants, stalls, a laundry workshop and warehouses.
Since September, 2012, more than 3,100 Mainlanders and 18 Hong Kong residents have been arrested for parallel goods trading.
Of the 233 Mainlanders prosecuted so far, 221 have been jailed.
