The two men also face charges of supply and offering to supply alpha-Pyrrolidinopentiophenone, also known as PVP.
PVP is described as a powerful synthetic stimulant.
A third man, a bodybuilder from Christchurch, is jointly charged with supplying PVP.
PVP reportedly causes the same stimulant reactions as the notorious "bath salts".
It is thought to be the first time anyone has been charged with supplying the drug in New Zealand.
It can be bought on the internet but PVP also comes with warnings that it has been tested only on rats and should not be consumed by people.
The brothers are cousins of former Warriors player Omar Slaimankhel.
They came to New Zealand as young children from Afghanistan after their family escaped from the war-torn country.
An Auckland Grammar School old boy, Khalid was a champion weightlifter during his high school days.
Both he and Walid competed at the Australasian championships in 2009.
He was referred to as "The Great Khalid" and his brother was referred to as "King" Walid.
Khalid is also a personal trainer and has worked at the family business, Prochem Pharmacy in Avondale.
A family member said: "The family is going through a lot already so we don't want it out in the public."
She said Walid was "not in a good state of mind at the moment".
"We're from a different culture, a different background. It's quite hard on the family."