Regis (left) used to represent Chambers, but no longer does so
Controversial sprinter Dwain Chambers could face legal action from his former agent John Regis over allegations in his forthcoming autobiography.
In an extract published on Monday, Chambers, who served a two-year ban for taking banned steroid THG, claimed Regis knew his client had taken drugs.
But Regis said there was "absolutely no truth" in the allegations.
"I'm not going to have my name destroyed - my job now is to clear my name," Regis told BBC Radio 5 Live.
"I'm very disappointed at these lies."
Chambers is with the Great Britain team in Turin for the European Indoor Championships and has defended the release of his book by saying he wanted to "close the door on the subject of drugs".
This on-going saga seems to be blighting the sport
BBC Radio 5 Live's Mike Costello
In serialised extracts from the book, Chambers calls British Olympic 400m champion Christine Ohuruogu "naive" for missing drug tests and is also critical of Sebastian Coe.
With Chambers' book set for release on Monday, Regis, who won silver and bronze medals at the 1988 and 1992 Olympics, added: "I think he has unwisely chosen to say false accusations.
"He is selling the book and he needs a caveat for the book to be productive. He has chosen a story that nobody would pick up on but his worst nightmare will happen.
"I want to make sure everybody understands who I am and I haven't changed from being the honest person they knew prior to these ridiculous thoughts by Mr Chambers."
The 31-year-old sprinter initially received "100%" support from his agent following his positive test for the banned steroid THG - supplied by the Balco laboratory in San Francisco.
"You believe your client and you fight for him," said Regis.
"You expect them to be honest. We believed in Dwain and didn't realise the level of cheating their whole group went through.
Chambers is hot-favourite for 60m gold this weekend in Turin
"You can only believe what the athlete tells you. His performances were improving so you assumed everything was working.
"When he was found guilty I was very disappointed he had lied. We believed in Dwain and didn't realise the level of cheating their whole group went though."
Chambers completed his ban in 2005, but was prevented from competing in most of the indoor meets early this year because they were organised by the EuroMeets Consortium.
Although Chambers is banned from competing at the Olympics, new UK Athletics head coach Charles Van Commenee said he should be welcomed back into the squad with open arms.
Regis, who revealed he had not spoken to his former athlete for three to four years, said he remained unconvinced by Chambers' remorse.
"Everything about this whole scenario was instigated by Mr Dwain Chambers," Regis said.
"He should stand up and be counted by his mistakes and not try to bring in other people to try to soften the blow. He should learn to stand up and accept responsibility."
Meanwhile, BBC Radio 5 Live athletics commentator Mike Costello, in Turin for the European Championships, believes the governing body for world athletics is likely to look at the content of the book and consider its negative impact.
"The IAAF has the power to ban him," Costello said, ahead of Saturday's 60m heats with Chambers up against fellow-Brits Simeon Williamson and Craig Pickering.
"(Regis) is worried about his reputation being tarnished. This on-going saga seems to be blighting the sport."
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