Legislation which will give doctors more power to decide whether asylum seekers should come to Australia for medical treatment has been passed into law by the Senate.

Key points: Labor, the Greens and four independents backed the bill in the Senate.

Labor, the Greens and four independents backed the bill in the Senate. Crucial crossbencher Derryn Hinch supported the bill after receiving a security briefing

Crucial crossbencher Derryn Hinch supported the bill after receiving a security briefing The Coalition claims the new law will restart boat arrivals, a claim Labor and the crossbench rejects

The Government suffered a historic loss when the same legislation was passed by the House of Representatives on Tuesday.

Labor, the Greens and four independents backed the bill in the Senate.

Senator Derryn Hinch, who supported the initial bill for medical evacuations last year, had asked for security briefings before the Senate voted on the bill.

The move was initially seen as a sign his support for the bill was wavering, but Senator Hinch ultimately decided to continue his support.

When he announced his decision, Senator Hinch said it was the hardest vote he had cast in the Upper House.

He said he was confident anyone who was transferred to Australia would remain in detention while receiving treatment.

"I think it's the right decision," Senator Hinch said.

The legislation will now go to the Governor-General for royal assent to become law, but the timeframe for this remains unclear.

As the Senate debated the bill, Prime Minister Scott Morrison announced the Government would reopen detention facilities on Christmas Island.

He said he expected the new medical evacuation laws could restart the people smuggling trade and Australia needed to be ramp up national security efforts as a result.

"My job now is to do everything within my power, and the power of the government, to ensure that what the Parliament has done to weaken our borders does not result in boats coming to Australia," he said.

Sorry, this video has expired Kerryn Phelps says there's no catalyst for more boats

Lower House crossbench MPs Kerryn Phelps and Julia Banks were in the Senate chamber during the final vote, and were among those who clapped when the bill passed.

"There is no need for applause, it's out of order," Senate President Scott Ryan told the chamber.

Greens senators hugged each other and Senator Hinch shook hands with Ms Phelps and Ms Banks.

Outside the Senate, Labor was quick to hit back at the Prime Minister and his suggestion the Opposition was encouraging people smuggling.

"The way [Scott Morrison] has behaved over the past 24 hours or so is beyond belief," Shadow Attorney-General Mark Dreyfus tweeted.

"He is happy to endorse lies, he has encouraged people smugglers to restart their evil trade and bullied journalists when they try to pull him up on it.

"Not fit to be PM of this country."

Sorry, this video has expired PM announces immigration measures in response to refugee bill's passage

Attorney-General Christian Porter went further than the Prime Minister, saying the Federal Government would not be able to stop two alleged sex offenders from entering Australia under the new laws.

Mr Porter said a refugee on Manus Island was facing sex abuse charges and someone on Nauru had been charged with indecently assaulting a child.

"None of those cases would result in the minister exercising discretion on transfer [to Australia for treatment]," he said.

Mr Porter said the new laws only allowed the minister to refuse entry to Australia if someone had been sentenced, not if they were only facing charges.

Christmas Island leaders criticise PM's announcement

Authorities on Christmas Island have labelled the Federal Government's decision to reopen the detention centre a "knee-jerk reaction".

Chief executive David Price said the island's medical services were ill-equipped to deal with refugees sent there in poor health.

"We've got a hospital, it doesn't do operations, people are medevaced out quite regularly here for medical reasons as it's only a small regional hospital," he said.

"We just wouldn't have the capacity here to deal with people coming here for medical reasons, both physically and mentally."