Michael Hartmann, who until last week was interior policy expert for the Social Democrats (SPD), "once consumed a fraction of the amount that is being discussed but hasn't touched it since," an unnamed person close the politician told the Allgemeine Zeitung in Mainz, the MP's constituency.
Hartmann's immunity was lifted last week amid allegations of drug use to allow Berlin police to search his apartment in the capital with sniffer dogs. No narcotics were found.
While the unnamed source was described by the newspaper as a confidant of the politician, Hartmann has maintained a rigid silence about the allegations.
He told a Mainz radio station on Monday evening that he will only respond to the allegations in direct conversation with the Attorney General’s Office.
Crystal meth or methamphetamine is a highly addictive hard drug which is often used recreationally for its effects as a euphoriant and potent aphrodisiac.
Hartmann, who has been a member of parliament since 2002, spoke out against the legalization of soft drugs in 2012.
Meanwhile, a woman identified only as Silke C. told a Berlin court on Monday that she had previously sold one gramme of crystal meth to a man with the same name in October 2013, media reported.
The deal took place at a cottage in the southwest of the capital that she used for business, with clients paying up to €120 for one gram of the drug, the woman said.
It was during observation of the location that police first suspected the MP of purchasing illegal substances.
The court hearing was due to continue on Tuesday.
SEE ALSO: Crystal meth use hits record level