Donald Trump isn't yet planning to come to Australia but the Greens want to block him from ever visiting.
Senator Nick McKim is seeking to amend proposed migration laws to give parliament the power to deny entry to any head of state or government on character grounds.
"He would fail the character test," Senator McKim said of the US president in parliament on Monday morning.
"He's green-lighted sexual assault on women. He's undermining the fundamental rule of law."
The move was quickly defeated in the Senate, after it was opposed by the government and opposition.
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Cabinet minister Michaelia Cash insisted the immigration minister had the power to make a written declaration to cease a special purpose visit if it was undesirable for that person to travel or remain in Australia.
The upper house is debating legislation that would strengthen existing laws allowing non-citizens who commit crimes in Australia, or pose a risk to the community, to have their visa refused or cancelled.
Senator McKim said the proposed legislation removed important safeguards and deprived those affected of information about their legal options.
"It's an incredibly Orwellian series of amendment bills we are seeing this government bring before the parliament that continue an erosion of the human rights and civil liberties in this country that so many Australians have fought to protect."
The legislation cleared parliament on Monday morning.
