China has dropped some of the world's leading technology brands from its approved state purchase lists, while approving thousands more locally made products, in what some say is a response to revelations of widespread Western cybersurveillance.

Others put the shift down to a protectionist impulse to shield China's domestic technology industry from competition.

Chief casualty is U.S. network equipment maker Cisco Systems Inc, which in 2012 counted 60 products on the Central Government Procurement Center's list, but by late 2014 had none, a Reuters analysis of official data shows.