The Trump administration announced plans last week for a new 12.5 per cent tariff on dozens of countries it says are failing to crack down on goods made with forced labour.
The proposed tariff was made public by US trade representative Jamieson Greer as part of an investigation into what Washington says were unfair trade practices by 60 countries.
But Trade Minister Don Farrell suggested the US' reason for the plan was not accepted by Australia.
"I don't see the two as being linked, as such," he said when asked if he would negotiate with the US about its claim Australia does not adequately address slavery in its supply chains.
"We have a range of mechanisms to deal with this in Australia, and we use those mechanisms to do our level best to end modern slavery."
The US Supreme Court in February ruled that US President Donald Trump's sweeping global tariffs, imposed unilaterally, were unconstitutional.
He then brought in a temporary 10 per cent global tariff, to remain in place until July 24. Some Australian exports, like beef and gold, are now exempt.
Senator Farrell said the higher rate could, for several days, be in place at the same time as the existing 10 per cent duty.
"That was the first question I asked my counterpart, Jamieson Greer," Senator Farrell said, in reference to a meeting with the US trade representative in Paris last week.
The US did not intend to enforce both tariffs at once, he said, so goods were likely to be subject to either the 12.5 or 10 per cent during the transition period, but there was little clarity as to which.
Australia is among 45 countries facing the higher 12.5 per cent rate, along with India, Japan, China., South Korea, Brazil and Switzerland.
Another group, which would include Britain, the European Union and Canada, would face a 10 per cent duty.
The US has opened channels for feedback on the plan until July 6 and Australia has put forward a bid for an exemption from the imposte.
Senator Farrell said he put forward Australia's case as strongly as possible.
"We have a free-trade agreement with the United States, which we honour," he said.
"We don't apply tariffs to any goods that come in from the United States. We expect the United States to do exactly the same and honour our free-trade agreement."
The US has a trade surplus with Australia, meaning Australia buys more from the US than it sells.
Hearings are due to begin on July 7, just before the existing US tariffs expire.
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