It is a leaf-based drug that, when chewed, releases juices that act as natural stimulants and is popular with the Somali community.
The Netherlands is used as a hub to transport khat imported from the Horn of Africa to other European countries.
There are concerns that the drug can cause psychosis or bring on schizophrenia.
The BBC's Anna Holligan in the Netherlands says the country has a traditionally liberal approach to soft drugs.
However, a Dutch government report cited noise, litter and the perceived public threat posed by men who chew khat as some of the reasons for outlawing the drug.
"I'm involved in the ban because it appears to cause serious problems, particularly in the Somali community," Dutch immigration minister Gerd Leers is quoted as saying by Radio Netherlands.
Source: www.talktofrank.com
He said that 10% of Somali men in the Netherlands were badly affected by the drug.
"They are lethargic and refuse to co-operate with the government or take responsibility for themselves or their families," he said.
Very few Dutch nationals use the drug, which is mainly chewed by people from Somalia, Ethiopia, Kenya and Yemen.
Our reporter says more than 25,000 Somalis now live in the Netherlands and as the population arrived, the use of khat in the country grew.
At the moment it is legally imported via Amsterdam's Schiphol Airport four times a week. Khat leaves need to be fresh, otherwise they lose their potency.
Last year, khat worth around $18m (£11.6m) was brought into the Netherlands.
The use of the stimulant is banned in the US, Canada and several other European countries.
But it is still available in the UK where it is legally sold in a small number of grocery stores.

The 22-year-old, who had two years remaining on his previous deal, will now remain at The Valley until the summer of 2018.
Pope had two spells on loan at York during the 2013-14 campaign, keeping 16 clean sheets in 24 appearances.
"I'm delighted that the club thinks I'm part of their long-term plan," Pope told the Charlton website.
He joined the Addicks from non-league side Bury Town in the summer of 2011 and made his debut in May 2013.
It remains Pope's sole senior appearance for Charlton, but he now hopes to establish himself in their starting XI.
"I'll work hard at Charlton and see what happens," he said.
"I think this is the right place to develop and, with the right coaches around me, hopefully I can do that. This is where I want to play my football."
The Dutch government has announced that it will ban the use of the mild narcotic khat.
[NEXT_CONCEPT]
Charlton Athletic goalkeeper Nick Pope has signed a new long-term contract with the Championship club.