The World Anti-Doping Agency (WADA) has issued a revised draft code inserting a proposed Olympic ban for serious doping offenders from January 2015.

The revision, if left in the final draft to be approved at a world conference on doping in sport in Johannesburg in November 2013, would mean athletes whose suspension ends before a Winter or Summer Games could be banned for one Olympic cycle.

The draft will have a third consultation phase between Dec 1 this year and March 1, 2013. The second phase ended on Friday.

Article 10.15 of the draft code, published on the WADA website (www.wada-ama.org), is in line with an International Olympic Committee rule which was outlawed after a Court of Arbitration for Sport (CAS) hearing last year.

That IOC ruling had excluded athletes banned for six months or more from the next Olympics.

The British Olympic Association (BOA) also lost a recent CAS hearing over its controversial by-law imposing a lifetime Olympic ban on British athletes failing dope tests.

The BOA had argued that the existing two-year sanction was an insufficient deterrent.

The CAS ruling cleared the way for British athletes with previous convictions, such as sprinter Dwain Chambers and cyclist David Millar, to be considered for selection for the London Olympics starting next month.

The revised WADA code says that, in certain circumstances, as an additional sanction an athlete "shall be ineligible to participate in the next Summer Olympic Games and the next Winter Olympic Games taking place after the end of the period of ineligibility otherwise imposed."