Victorian Labor MP Khalil Eideh doesn't believe his dual Syrian and Australian citizenship or his recent trips to Syria influenced a US decision to refuse him entry while on official parliamentary business.
Mr Eideh returned to Melbourne on Saturday after he was stopped from boarding a flight to the US from Canada 48 hours earlier.
"I've been discriminated against," the upper house MP told reporters at Melbourne airport.
"I'm very, very disappointed and frustrated."
Mr Eideh, who was born in Lebanon to Syrian parents, was on an official study tour with other MPs when a United Airlines staffer in Vancouver told him he was not allowed to board a flight to Denver.
"There was no explanation whatsoever," he said.
"They told me 'unfortunately it's blocked, we can't let you in the plane'."
Mr Eideh said he had a visa for his US travels, and that US authorities had not raised any issues with him during the application process.
He does have family in Syria, and said he last visited the country over the Christmas break.
But he does not think US President Donald Trump's travel ban, which bars citizens of Sudan, Somalia, Iran, Yemen, Syria and Libya from travelling to the US, is behind his refused entry.
"It shouldn't. I'm not sure if that's the reason but that's unacceptable," Mr Eideh said.
"I'm representing the Australian people, the Victorian people ... I was doing a job on behalf of the Victorian government."
The US Embassy is yet to comment on the reasons behind the decision, but Mr Eideh signed a letter in 2002 professing loyalty to Syrian dictator Bashar Al- Assad.
The letter, which was made public when Mr Eideh was preselected, was seeking to get the Syrian Honorary Counsel in Melbourne removed because he played a "divisive" role in the local community.
Senator Kim Carr, who met Mr Eideh at Melbourne airport, said he was "a victim of Trumpism".
"I find it an extraordinary proposition that a member of an Australian parliament, with a valid visa, travelling on an official passport, undertaking parliamentary work, can be stopped from entering the United States without
explanation," he said.
"Quite clearly Khalil has been a victim of Trumpism and what we're seeing here is the chaos that reigns in the United States."
The Labor party has asked Australia's embassy in Washington for an explanation for Mr Eideh's refusal.
