US Senator Ted Cruz has continued to call for Muslim refugees to be barred from entering the United States, opening borders exclusively to displaced Christians.

He argued that there is no "meaningful risk" that Christians would commit terrorist acts.

"There is no meaningful risk of Christians committing acts of terror. If there were a group of radical Christians pledging to murder anyone who had a different religious view than they, we would have a different national security situation," Cruz told reporters.

"But it is precisely the Obama administration's unwillingness to recognize that or ask those questions that makes them so unable to fight this enemy [ISIS]. Because they pretend as if there is no religious aspect to this," he said.

He did not specify how he would determine the faith of refugees, but insisted that it was "lunacy" to allow Muslim refugees into the US.

"We can't roll the dice with the safety of Americans and bring in people for whom there is an unacceptable risk that they could be jihadists coming here to kill Americans," Cruz said.

"We just saw in Paris what happens when a country allows ISIS terrorists to come in as refugees and the result can be a horrific loss of life."

This position held by Cruz is a shift from his former view expressed on Fox News in early 2014 that America should allow Syrian refugees into the nation:

"We have welcomed refugees, the tired, huddled masses for centuries. That's been the history of the United States. We should continue to do so," he said.

"We have to continue to be vigilant to make sure those coming are not affiliated with the terrorists, but we can do that."

On Sunday he said that the landscape has changed since early 2014:

"We've seen a number of things change. We've seen the rise of ISIS, we've seen the manifest evil of their terrorism, we've seen also the enormous failures of the Obama administration's intelligence operations," he said.

The Obama administration "does not have the information" to determine who among the refugees is a terrorist, he claimed.

"Sadly, it appears that at least one of the terrorists who committed these attacks in Paris came as a refugee in Syria," he said.

"So what does President Obama and Hillary Clinton want to do? Bring tens of thousands of them to America and put them here."

Instead of closing the borders entirely, Cruz said "We need to be working to provide a safe haven for those Christians who are being persecuted and facing genocide, and at the same time we shouldn't be letting terrorists into America."