Medics have long called for the move, saying that it could reduce the incidence of conditions like spina bifida.
Pregnant women and those trying to conceive are advised to take a daily supplement of 400 micrograms of folic acid, at least until the 12th week of pregnancy.
But many women do not take the supplements - especially if their pregnancy is unplanned.
The NHS Choices website says that folic acid is important to foetus growth and can significantly reduce the risk of neural tube defects such as spina bifida.
Ministers have reportedly backed a plan to fortify flour with folic acid - which already happens in more than 80 countries.
It has previously been recommended that wheat flour is fortified with folic acid to improve the "folate status" of the population and reduce the risk of these birth defects.
Kate Steele, chief executive of the charity Shine, which helps families affected by neural tube defects, told the Guardian: "Mandatory fortification will be a game-changer for the UK.
"A Government decision to introduce mandatory fortification will mean a major positive impact for the health and well-being of babies born in the future. In many cases, it will be the difference between life and death."
A Department of Health and Social care spokeswoman said: "Ministers are considering expert advice and will respond in due course."