Khawaja was reprimanded by ICC for wearing black armband in support of Palestine.
Khawaja, on the eve of the first Test, was seen wearing shoes with the messages "all lives are equal" and "freedom is a human right" to raise awareness of the humanitarian crisis in Gaza.
The first Pakistani-origin cricketer to play for Australia, Khwaja is a devout Muslim and has been vocal about his support for Hamas-backed Palestine in its conflict with Israel in Gaza.
There was no official statement when Khawaja wore the armband on the first day in Perth, but at the time it was understood to be about the video he'd posted on social media after being told he could not show the messages on his shoes.
Under the level that Khawaja has been charged with, a reprimand is the most serious punishment so if that did eventuate it would not leave him in any doubt for the Boxing Day Test against Pakistan. Even a fourth such sanction in 12 months would only be a penalty of 75% of the match fee rather than a suspension.
“Usman Khawaja has been charged with breaching Clause F of the Clothing and Equipment Regulations. Usman displayed a personal message (armband) during the first Test Match against Pakistan without seeking the prior approval of Cricket Australia and the ICC to display it, as required in the regulations for personal messages. This is a breach under the category of an 'other breach' and the sanction for a first offense is a reprimand,” an ICC spokesperson told ESPNCricinfo.
On the other hand, Khawaja said that he did not believe ICC was implementing its regulations consistently.
"They asked me on day two [in Perth] what it was for and told them it was for a personal bereavement. I never stated it was for anything else. The shoes were a different matter, I'm happy to say that. The armband makes no sense to me. I followed all the regulations and past precedents, guys who put stickers on their bats, and names on their shoes, did all sorts of things in the past without ICC approval and never been reprimanded.
I respect the ICC and the rules and regulations they have. I will be asking them and contesting whether they make it fair and equitable for everyone and whether they have consistency in how they officiate. That consistency hasn't been done yet. I was very open and honest with that. I'll deal with that with the ICC,” Khawaja said at MCG ahead of the second Test.
Cricket Australia CEO Nick Hockley said that the board was in ongoing conversations with the ICC over whether Khawaja may communicate his message, though it remains unclear whether those discussions would be concluded in time for the Boxing Day Test.
Though black armbands are regularly worn by players to mourn the deaths of former players, family members, or other significant individuals, they need permission from the national board and the ICC before they are worn.
(ANI inputs)