The expansion is about 2.6 times faster than the growth of the general industrial production index during the reviewed period, data from the General Statistics Office (GSO) show.
It is also an auspicious start for the industry to achieve the record productivity of 14.9 million tonnes this year, compared to about 10.92 million tonnes in 2011 and 12.5 million tonnes in 2015.
The production growth is partly attributable to an increase in domestic demand as 12.53 million tonnes of iron and steel products were consumed from January to May, or more than 2.5 million tonnes each month.
Exports of those commodities also climbed to over 240,000 tonnes a month during the period, the highest ever volume. However, export prices dropped 26.3 % from a year earlier following a 13.5 % fall in 2015.
Meanwhile, over 1.58 million tonnes of iron and steel products were imported into Vietnam each month between January and May, much higher than the monthly average in the previous years.
Import prices in the five months sank 32.5 % year on year, leading to a decline of US$1.45 billion in iron and steel import turnover despite a 50.5 % surge in import volume.
The strong import is said to help Vietnamese businesses prepare for future economic recovery but also put pressure on domestic manufacturing.