But almost seven months on, the controversial proposal has all but disappeared from the government's agenda, prompting speculation it was only advanced to elicit a temporary bounce in the polls.

The bill, which stops anyone taken to Nauru and Manus Island after July 19, 2013 from ever being granted a visa to come to Australia, was rushed into Parliament by Immigration Minister Peter Dutton in November.

This week marks six months since it passed the lower house, but it has never been brought on for debate in the Senate and crossbenchers have not been engaged in negotiations despite a chance of success.

"It's basically just parked," a senior government source told Fairfax Media. "I think it will come to a head in the second half of the year. The door's not completely closed."

Under the proposed law, asylum seekers who came by boat would not be eligible for even a tourist, business or spousal visa to Australia, unless granted an exception by the immigration minister.

The announcement last year sparked a flurry of outcry from refugee advocates and lawyers, who warned it was cruel and could breach international law - an argument the government rejects.

The move also prompted an unusual and extraordinary rebuke from former prime minister Kevin Rudd, who called it "pure politics designed to appease the xenophobes" and protect Coalition votes from One Nation.

Labor's citizenship spokesman Tony Burke suggested on Q&A last month the ban had only been mooted to secure a polling bounce for the government.

"The announcement was made, we talked about it all week, the legislation went through the House of Representatives - never heard of again," he said. "[The] government never returned to it. Just disappeared."

At the time, Mr Dutton said the bill was "critical to support key government border protection policies". Days later, a deal to send refugees from Manus Island and Nauru to the US was announced, raising the prospect of back-door access to Australia.

A senior government source last week said the visa ban was still necessary because "if the US deal works and people somehow game the system and end up here, it'll destroy the government's message".

The bill's passage through the Senate is far from assured: Labor and the Greens will oppose it, while the crucial Nick Xenophon??? Team has a conscience vote.

Senator Xenophon told Fairfax Media he was prepared to negotiate but had not been approached.

"We haven't heard from the government for quite some time about this," he said. "If they want to discuss it with us then obviously we will. I currently can't see it getting through."

A spokeswoman for Mr Dutton would not comment on the bill's delay, but said Labor's opposition "underscores the division on border security within Labor and gives hope to people smugglers".