Jared Tallent will wait out a doping investigation into another Olympic conqueror after the athlete who beat him in Rio was provisionally suspended over an alleged breach.

In what must be distressing news for Australia's 2012 Olympic champion and passionate anti-doping campaigner, Slovakia's Matej Toth has been asked by the International Association of Athletics Federations to explain anomalies in his athlete biological passport, which tracks blood data over time for signs of drug use.

Toth beat Tallent to gold in the 50km race walk at both last year's Rio Games and the 2015 world championships, but the Australian has always believed his friend was clean.

Toth revealed his situation overnight and announced his withdrawal from next month's world titles in London, where Tallent will compete as the favourite.

The 34-year-old Slovakian, who has spoken out against doping and backed the Russian team being barred from Rio, said he was shocked by the IAAF's notification and suffering physically and mentally as a result.

"Since I have always stood up against any unfair practices throughout my career, I totally rule out any misconduct," Toth said.

"In this sense, this message has shocked me."

Tallent has decided not to comment until the investigation has run its course, but the revelation will be tough to hear for the man who last year retrospectively received his London 2012 gold medal after Russian winner Sergey Kirdyapkin was found to be a drug cheat.

Toth faces a four-year ban and, should the IAAF conclude his explanation is insufficient and target him for doping, opens the possibility of Tallent receiving a second Olympic gold medal years down the line.

A guilty finding would come as a blow to a race-walking community already reeling from a string of doping bans for Russian walkers who dominated major championships for many years.

Tallent's belief in the Slovakian's drug-free stance was clear after last year's Olympic race, which the Australian led at the 40km mark but, after losing his legs with just two of the 25 laps remaining, succumbed to a motoring Toth.

"I didn't have to worry about any cheats in the race who were going to spoil the party for all the clean athletes," Tallent said at the time.

Tallent is set to depart for a final training camp in Switzerland before the world championships beginning early August.

AP