Australian Sports Anti-Doping Authority head Ben McDevitt says he is very confident that Essendon players received banned drugs in an 2012 injection program, despite a tribunal finding to the contrary.

In a further sobering statement for those believing Essendon, the AFL and 34 footballers who were this week pronounced not guilty of taking banned drugs were entirely in the clear, McDevitt has told Fairfax Media: "My sense is that we're still only part way through the journey."

The CEO who will ultimately say whether ASADA appeals the not-guilty judgment by an AFL anti-doping tribunal of 34 current and ex-footballers, McDevitt has revealed he expects to have crucial evidence concerning discredited sport scientist Stephen Dank within days.

This information, which McDevitt admitted he was surprised not to receive from the AFL's anti-doping tribunal on Tuesday when it announced its judgment, will inform the government-funded national drug agency's next move.

With the clock now ticking on the most significant decision in ASADA's history – the agency has a 21-day appeal window before any appeal would have to come from the World Anti-Doping Agency – McDevitt indicated he feels no less convinced about the strength of his drug agency's case.

Asked about his confidence that Essendon players received banned drugs, in light of a unanimous not-guilty verdict from a three-member tribunal, McDevitt said on Wednesday: "I still believe that's the case.

"I'm very confident. It's whether or not you can prove it."

Signalling he will pay little mind to the much-criticised two-year  Essendon drugs probe, and the toll it has taken on Australian sport and Australian football, McDevitt said the urging of AFL boss Gillon McLachlan for ASADA not to appeal is irrelevant.

"It's my decision," he said.

"I need to make the decision, and we need to think about it really, really carefully.

"It's not a matter of sort of saying 'everything's done here, move on folks, nothing to see here'. My sense is that we're still only part way through the journey."

Asked to expand on this, McDevitt said: "We may well be part way through the journey, perhaps."

Less than 24 hours after the ruling on the players, McDevitt was unprepared to say whether ASADA was more or less likely to appeal the verdict: "No. I really haven't formed a position yet. I need to sit down with our legal advisers, the government solicitor, with the people who presented our case, and talk it through with them.

"We're just going into an Easter period. I'd like to have the Dank material as well. I'd like to go through it at the same time if I'm going to bring everyone together."

Health Minister Sussan Ley has also weighed in, saying that regardless of the tribunal's verdict, the initial report found an experimental environment that was never adequately controlled.

"Any injection of unknown substances into athletes in order to push the boundaries of sporting achievement is unacceptable," she said. "It shows a complete disregard for player safety and welfare."

Eager to dissect the AFL anti-doping tribunal's verdict and reasoning on Dank, who oversaw the high-volume injection program at Essendon, McDevitt revealed ASADA had expected to have the information by now.

While the anti-doping tribunal announced it was not comfortably satisfied that the Essendon players received banned drug thymosin beta-4 through the injection regimen - and thereby declared them not guilty of an anti-doping rule violation – it said next to nothing publicly about Dank.

A statement issued on Tuesday by the anti-doping tribunal's chairman, former Victorian County Court Judge David Jones, referred only to a decision against a former Essendon support person that would "be handed down at a later date, together with reasons for that decision".

This surprised ASADA, which was expecting a verdict on the players and the figure who designed the injection program - which McDevitt derided as "utterly disgraceful"  - almost as soon as the players ruling was declared.

Dank is the sole known former Essendon support person who has been accused of committing a doping offence by ASADA to date.

"We've got an indication from the tribunal that it would be after Easter [that] we would get the Dank material," McDevitt said.

"My expectation had been we would get the Dank material yesterday [Tuesday].

"I would rather look at the whole lot in its totality before making a decision [on whether ASADA appeals]."

McDevitt said the reasons behind the length of the most high-profile anti-doping investigation in the history of Australian sport were "multiple".

"When you also look at the significant doping investigations overseas, the Lance Armstrong examples and those sort of things, two years isn't an especially long time."