At the 2017 world titles in London, Peacock's best of 82.46 metres was the longest throw in history not to qualify for a final.

But of the 13 rivals who edged him out, Indian Davinder Singh and Greece's Ioannis Kyriazis have both since been handed provisional suspensions after testing positive for banned substances.

"Naturally, I'm annoyed and angry about it, but what can you do?" Peacock said.

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"In athletics there's quite a long history of doping and cheating so I'm not overly surprised but I guess this is a bit close to home.

"I was pretty frustrated at the time because I was throwing quite well and it's frustrating now, but there's not much you can do about it."

Singh was suspended later in 2017 after his urine samples tested positive for anabolic steroids but earlier this year was controversially cleared by both the Athletics Integrity Unit and World Anti Doping Authority after India's testing lab withdrew his adverse analytical finding.

Earlier this month, the AIU confirmed that Kyriazis had also been provisionally suspended after testing positive.

A veteran of three world championships and the Rio Olympics with five national titles and two Commonwealth Games medals to his name, Hobart-born Peacock retains vivid memories of the 2017 event.

"I had two 82m throws that day and automatic qualification to get to the final was 83m," he said.

"I was in the first pool and was in the warm-up area during the second pool watching the live results on my phone and it just kept saying 'qualified, qualified, qualified' so I knew I would be pushed out.

"I am annoyed because it would have been massive for me because I've been to a few major championships and am yet to make a final. And once you're in a final, anything can happen.

"You've just got to keep trying to be your best.

"I still love the sport, but it is frustrating."

Peacock's predicament has been shared by numerous clean athletes as drug testing methods have improved, with compatriot Jared Tallent among the highest profile cases after being initially denied a race walking Olympic gold medal by a Russian drug cheat.

"A lot of athletes have been affected over the years and a few Aussies have been bumped up places," Peacock said.

"Look at him (Tallent) - he never got his moment to shine in the limelight."

Peacock's manager and IAAF technical official Brian Roe said such cases highlight the challenges facing clean athletes competing on the world scene.

"It shows the frustration for people like Hamish when cheaters cost them at the time of their best chance for success," he said.

"Being a world championships finalist would have been a big feather in Hamish's cap and who knows what he could have achieved if he'd been in the final."

As he heads to next week's Oceania championships in Townsville eyeing qualification to this year's world championships in Doha, Qatar, at the end of September, Peacock remains confident he can still reach a major final.

"Absolutely. I've been in a lull for 12 months with a niggling injury and things going on in my life, but there's no rush.

"I'm still only 28, that's pretty young in javelin. The world record was set 23 years ago (by the Czech Republic's triple Olympic champion Jan Zelezny) when he was 30 so there's no real age limit."

With a personal best of 84.39m from back in 2016 and a season's best of 78.12m set when winning the national title in Sydney, Peacock is expecting strong competition from world junior champion Nash Lowis, fellow Queenslander Liam O'Brien (PB 81.36m) and New Zealander Ben Langton-Burnell (PB 82.44).

"I've been training a lot better so I'm pretty confident I will throw better than earlier in the year.

"In previous years this has been a development competition for lower level athletes but this year it is an Olympic point scoring event which means a lot of Australia's best will be there."

Seeking another throw of 83m to lock in a fourth senior world champs, the rest of Peacock's season will be determined after the Oceania titles.

"It depends how I go in Townsville. I have not got any plans yet," he said. "The qualifying period for world champs goes until September so if I'm throwing well I will try and qualify in Australia, otherwise I'll maybe go to Europe."

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