CHINA's factories lost more momentum in November, according to a key monthly survey of manufacturing firms, with domestic demand again looking bleak despite a recent boost in infrastructure spending.

The official manufacturing Purchasing Managers' Index (PMI) dropped to 50.0 last month from 50.2 in October, marking the lowest reading in over two years and falling short of market forecasts (Bloomberg media: 50.2). A score of 50 denotes no growth in the sector, with anything above indicating expansion.

New orders were particularly weak, the data shows, reflecting China's broader cyclical difficulties.

The official non-manufacturing PMI, also released on Friday, fell from 53.9 to a 15-month low of 53.4, on the back of a steep drop in construction activity in November.

"With credit growth still slowing and regulators yet to unleash off-budget fiscal support, growth is likely to weaken further in the coming months," said Julian Evans-Pritchard, senior China economist at Capital Economics

A regular monitoring report of G20 trade policies has found that US restrictions have affected US$369 billion of Chinese goods - almost $90 billion more than the commonly cited figure.

The Global Trade Alert, authored by two University of St Gallen academics and quoted by Reuters, said that media reports stating that $278 billion of Chinese imports have so far been hit with US tariffs do not take into account other restrictive measures. 

"This year has also seen $47 billion of Chinese good shipments to the United States targeted by other US trade distortions," the report read. "Furthermore, over $43 billion of Chinese exports have been caught up in other US trade distortions that affect multiple countries."

Including the additional trade distortions, the reports add, a third more Chinese exports are falling under the influence of the trade war than is commonly reported.