It comes after the World Athletics Disciplinary Tribunal dismissed the charges against the women's 400 metres world champion, who was facing a two-year ban from the sport which would have seen her miss the Tokyo 2020 Olympics.

The 22-year-old has escaped a ban after a drugs tester, Enrique Martinez, knocked on a storage cupboard door rather than Naser's apartment after numbering on the flat left him confused.

On Twitter, Bańka revealed that WADA would analyse the case and appeal if needed.

"As it relates to Salwa Eid Naser and the World Athletics Disciplinary Tribunal decision on her case I am concerned," said Bańka.

"WADA will analyse it carefully and exercise its right to appeal if necessary."

The Athletics Integrity Unit (AIU) had charged Naser with four alleged whereabouts failures in June, and it was revealed that she was under investigation when she won her world title in Doha last year.

This included a filing failure on March 16, 2019 and three missed tests on March 12 and April 12 of last year and January 24 of this year.

Missing three tests within 12 months is the equivalent of a doping failure and Naser had been provisionally banned after the charges were brought.

However, the Disciplinary Tribunal has ruled the alleged violation in April 2019 should not stand, which means Naser has not missed three tests inside the 12-month window.

Filing failures are always backdated to the start of the quarter, so in Naser's case January 1, 2019.

Martinez was looking for Flat 11 in Naser's building and found two doors close to one another.

The left hand door had the number 11 at its side and the right hand door had the number 954 and an intercom, with the number 12 underneath.

This caused confusion as the numbers 11 and 12 actually referred to car parking spaces and were not apartment numbers.

Naser's apartment 11 was behind the right hand door marked 954, and the left hand door marked 11 was in fact a storage unit containing nothing but gas cannisters.

Martinez knocked every five minutes for the required hour, but received no response.

Martinez should not be blamed, the Tribunal ruled, as the door numbering is "extremely confusing".

He had earlier been given a building number which did not exist but found the correct place as he had a picture from a previous visit.

The test was scheduled for between 6am and 7am but Martinez "went beyond the call of duty" and returned later in the day as well, when he failed to find Naser again for the same reason.

He also unsuccessfully tried to find her at Bahrain's national stadium, an act the Tribunal said went "well beyond his mission".

In clearing Naser, the Tribunal said: "Mr Martinez, quite simply, knocked on the wrong door."

However, concerns from the Tribunal were raised over Naser's inability to use the ADAMS system which allows athletes to enter whereabouts details and other information, so they can be drugs-tested at random.

Martinez did try to phone Naser, but the Tribunal heard her details were not up to date and there was no number which worked.

The Tribunal heard she has "never been able to submit her own whereabouts information, let alone successfully log in" and the Bahrain Athletics Association has assigned a member of staff to do so for her.

It was agreed that Naser "did not help herself" in many regards due to the lack of information she had submitted, particularly as she had been warned about missed tests before.

"This was a case very much on the borderline and we hope the athlete will learn from the experience and heed the AIU's warnings," the Tribunal said. 

After switching allegiance from Nigeria, Naser has become one of the most notable athletes in Asia, having run the third fastest women's 400m in history at the 2019 World Athletics Championships in Doha.

She won the world title in a time of 48.14sec in Qatar's capital, the fastest time since East German Marita Koch set the world record of 47.60 in 1985.

In the Doha final, the top five all recorded a personal best, with The Bahamas' silver medallist Shaunae Miller-Uibo setting an area record alongside Naser.

The AIU also has the opportunity to appeal the decision to the Court of Arbitration for Sport.

World Athletics stressed that it had "no input into case management and decisions" when contacted for comment on the Naser case.

"In 2017, World Athletics (then the IAAF) set up an independent system to manage anti-doping matters in order to separate it completely from the administration of the sport", it said in a statement. 

"The Athletics Integrity Unit was established to oversee testing, investigation and cases. 

"The Disciplinary Tribunal, which comprises independent legal professionals, decides on cases and is also a separate body. 

"World Athletics has no input into case management and decisions. 

"We understand that the time this process takes can be frustrating, but the system must be independent, robust and thorough in order to maintain integrity."