But there are no plans for a specific rule to ban offenders from the Olympics.
Currently, athletes found guilty of a first major doping offence are handed a two-year ban with any subsequent positive test incurring a life-ban.
The longer ban would be introduced for offences that include the use of anabolic steroids, human growth hormone, masking agents and trafficking, according to a second draft of the 2015 WADA code which was reviewed over the weekend.
"It is clear ... there is a strong desire in the world of sport, from governments and within the anti-doping community to strengthen the sanction articles in the code," WADA President John Fahey said.
"This second draft has done that, doubling the length of suspension for serious offenders and widening the scope for anti-doping organisations to impose lifetime bans."
The draft does not, however, consider a former International Olympic Committee rule regarding Olympic participation, which was ruled in non-compliance with the WADA Code in 2011 by sport's highest court, the Court of Arbitration for Sport.
The IOC rule, introduced in 2008, banned athletes from participating at the next Olympic Games if they had been suspended for six months or longer.
After the rule was ruled non-compliant, Britain was forced to overturn lifetime Olympic bans on their drug cheats.
"The rationale is if more four-year sanctions are delivered, then there won't be any need for (the IOC rule) because the athletes will be missing the next Olympics," WADA spokesman Terence O'Rorke said.
The new WADA Code draft also includes a proposal that to be prohibited, substances or methods must be performance enhancing, contrary to the spirit of sport or contrary to the health of athletes.
The proposed code will undergo further review between now and March 2013, when it will be presented to the WADA Foundation Board before a final draft is prepared for ratification at the world anti-doping conference in Johannesburg next November.
"Athletes must know that there is a heavy price to pay for intentional doping," Fahey said. "I am confident this draft will deliver that message loud and clear."
WADA also said its funding would be frozen for a second successive year at approximately $28 million (£17.5 million) in 2013.
"This freeze is not ideal for the fight against doping in sport," Fahey said. "It is widely accepted that doping is a major issue no longer restricted to the sporting world, and that it must be addressed by society as a whole."
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