Landis, who was stripped of the 2006 Tour de France title after testing positive for testosterone, said that Pepe Marti was "nothing more than a known drug dealer" in a new interview with German television station ARD.
Marti was a coach for Landis's US Postal team where, according to a series of emails sent by Landis to the US Federation and the UCI earlier this year, he was systematically doped from 2002.
In that correspondence Landis also alleged that Marti had supplied him and other team-mates, including Lance Armstrong, George Hincapie and Levi Leipheimer, with growth hormones.
"Pepe was a supplier of drugs to US Postal when I was in the team," Landis said in his latest interview.
"I often used him to buy growth hormones, EPO and other doping products. He was not a coach. He was nothing more than a known drug dealer. "
Contador, with whom Marti worked with at Discovery, was quick to respond to the latest comments from Landis.
"Alberto knew Martiwhen he was at Discovery," Contador’s spokesman, Jacinto Vidarte, said.
"As he was then a coach at the team, he was in charge of training. He also fulfilled that role at Astana as he moved into the Kazakh set-up after the North American team folded.
"This year, the only people responsible for Alberto’s calendar and preparation are the members of the Saxo Bank team and Bjarne Riis. What he says about Marti is false."
Contador tested positive for trace of clenbuterol during the 2010 Tour de France, which he won. He is currently awaiting a CAS ruling on the case.