The performance was driven by a growth in new orders, with December's level of production the strongest in the current 17 month sequence of growth, and third-fastest in the Investec Manufacturing PMI Ireland surveys history.
Andrew Harker, associate director at IHS Markit, which compiles the survey, said "The Vietnamese manufacturing sector recorded a welcome return to growth of output in December, supported by a solid and accelerated increase in new orders". The index has held above the 50 line separating growth from contraction for every month since November 2013.
Increased consumer demand also reinforced optimism that output will increase in the next 12 months.
However, Zhong cautioned that "downward pressure" on growth next year will remain due to "tightening monetary policy and strengthening oversight on local government financing".
A private survey that focuses on small and medium-sized firms in showed that manufacturing activity picked up at a slower pace in November. It was the first slowdown in growth since early 2016. It also vowed to keep a tighter grip on the money supply in a much more hawkish message than it had at the previous year's meeting.
The figure pointed to a marked monthly improvement in the business sector and was the strongest reading since August, the Istanbul Chamber of Industry and IHS Markit said. Compared with the official gauge's coverage of firms including large state-owned companies, the Caixin PMI tends to track small, private manufacturers more closely. On the price front, Goods and Services Tax (GST) continued to lead to greater raw material costs, with input cost inflation accelerating to the sharpest since April. This was consistent with the strongest improvement in the health of the sector since December 2012.