Most wine labels "understate the true level of alcohol in the bottle," the Mail Online reports.
Research published by the American Association of Wine Economists found that in nearly 60 per cent of 129,000 bottles of plonk tested, the alcohol content was 0.5 per cent higher than the label suggested.
While this is still within legal limits, it may be due to the fact that wine producers are responding to a demand for stronger, fruitier wines.
However, according to alcoholconcern.org.uk, some producers are deliberately misleading consumers about the true alcohol content as they deemed wines over 13 per cent alcohol were not saleable in some markets, i.e. among the health-conscious.
The study revealed that while this occurred in wines from all the main wine-producing countries, the "worst offenders" were Chile, Argentina and the USA.
Commenting on the findings, Don Shenker, chief executive of Alcohol Concern, said: "It is simply irresponsible for wine producers to understate the strength of wines for marketing purposes or any other reason. Consumers deserve to be treated with more respect.
"This will do considerable damage to an industry claiming to act responsibly to reduce alcohol harms, it's high time we had an independent and mandatory scrutiny of alcohol labelling, with possibly sanctions in place for non-compliance."