President John Magufuli has condemned contraception and urged Tanzanians to continue reproducing.
Speaking during a public rally on Sunday, Magufuli said only 'lazy people' use birth control.
"You have cattle. You are big farmers. You can feed your children. Why then resort to birth control? This is my opinion, I see no reason to control births in Tanzania.
"Those going for family planning are lazy because they are afraid they will not be able to feed their children," Magufuli is quoted by The Citizen newspaper as saying.
He cited the declining population growth in parts of Europe that has led to a workforce crisis.
"I have travelled to Europe and elsewhere and have seen the harmful effects of birth control. Some countries are now facing declining population growth. They are short of manpower," Magufuli added.
Tanzania has a population of around 60 million people, up from 10 million at independence in 1961.