Zaharie’s family and friends have long strongly rejected such claims as baseless.
Malaysia’s former premier Najib Razak, who was in power during the tragedy, said suspicions over the disappearance weren’t made public and there was no proof that the pilot was responsible.
“It would have been deemed unfair and legally irresponsible since the black boxes and cockpit voice recorders had not been found,” he told online portal Free Malaysia Today.
“There was no conclusive proof whether the pilot was solely or jointly responsible.”
Najib said the scenario involving the pilot was “never ruled out” during the search for the plane.
Azharuddin Abdul Rahman, the former head of Malaysia’s civil aviation regulator, criticised Abbott’s remarks and said there was not sufficient proof to support the idea.
“It is only a theory,” Azharuddin, who led the regulator when Flight MH370 disappeared, told AFP.
“You do this speculation and it will hurt the next of kin. The family of the pilot will also feel very bad because you are making an accusation without any proof.”
In 2016, Malaysian officials revealed the pilot had plotted a path over the Indian Ocean on a home flight simulator but stressed this did not prove he deliberately crashed the plane.
A final report into the tragedy released in 2018 pointed to failings by air traffic control and said the course of the plane was changed manually.
But they failed to come up with any firm conclusions, leaving relatives angry and disappointed.
Six passengers were Australian, including four from Queensland state, where Premier Annastacia Palaszczuk this week suggested authorities may pursue an inquest into their deaths.