New South Wales Premier Mike Baird says Australia has reached a fork in the road in its refugee policy and will be denying its history if it closes the door on new arrivals.

In an Australia Day address given on Friday, Mr Baird warned of the dangers of what he called anti-immigration politics in Australia and around the world.

He said the country owed much of its success to migrants, and he feared what would happen if refugees were turned away.

"We are one of he most successful and multicultural nations in the world," Mr Baird said.

"But I believe we are potentially at risk of losing what makes Australia the best place in the world to live, because some want to shut our doors and avert their eyes."

In his speech, Mr Baird spoke of Deng Thiak Adut, a former child soldier in Sudan who is now a refugee lawyer in Australia, who this week spoke at an event in the lead-up to Australia Day.

Deng Thiak Adut, once a child soldier in Sudan, is now a refugee lawyer. ( Supplied: Sally Tstoutas, file photo )

"What an amazing country we are part of," he said.

"Because we welcomed Deng, we sheltered him, we gave him clothes, food and a chance to learn, and he seized that opportunity, and now he is working in his community giving back to those who, like him, once had no voice."

The Premier said Australia owed a large part of its character to the success of people like Mr Adut.

"And to our kindness, compassion in sharing our luck and giving them a chance," he said.

"Deng is what happens when generosity meets opportunity.

"When listening yesterday, you could hear pride in his words and he reminded us poignantly that in our national anthem are the words: 'For those [who've] come across the seas, we've boundless plains to share'."

Mr Baird said as he was listening to Mr Adut deliver his address he felt proud, but also fearful.

"My genuine and honest fear is what will happen to Australia if shut people such as Deng out, whether it be out of fear or ignorance," he said.

The Premier said Australia must face threats and arm its security forces to protect the borders appropriately.

"But we must not lose sight of who we are that makes us so great," he said.

"I say we have a choice: We can continue on the path that brought this nation to where we are today, or we can let fear blind us and fear infect us.

"To shut our doors to refugees, as many here and around the world are calling for, is to deny our history, to deny our character.

"In a quest for personal comfort let us not sacrifice who we are above all, which is welcoming, compassionate and inclusive."