The German parliament has approved controversial plans to legalise the personal use of cannabis.

The measure was passed by Germany’s lower house, the Bundestag, on Friday.

From 1 April, adults will be able to buy up to 25 grams (one ounce) of the drug a day, or up to 50 grams (two ounces) per month for recreational use.

The figure will be capped at 30 grams a month for under-21s.

Users will also be able to grow up to three plants each for private consumption

Germany’s upper house, which represents 16 state governments, could in principle delay the legislation, though it does not formally require the chamber’s approval.

Bavaria’s conservative state government has also said it would examine whether legal action could be taken to halt the law.

Health minister Karl Lauterbach said: “We have two goals: to crack down on the black market and improved protection of children and young people.”

He said that Germany’s current laws had failed, as usage is growing and the country is facing increasing problems from contaminated or overly-concentrated batches. An estimated 4.5 million Germans use the drug.