Daniel Trenchard-Harry has been missing from his home near Albury since Monday.
The 28-year-old has an intellectual disability.
A search of bushland involving the police helicopter and officers on horseback will resume on Thursday morning.
A 28 year-old man who has been missing for four days was last seen walking away from his home in southern New South Wales without shoes, prompting a search.
Police are urging anyone who sees Daniel Tranchard-Harry not to approach him, but instead to keep their distance and try talking to him about fishing.
Mr Trenchard- Harry, who has an intellectual disability, left his home on Centaur Road at Hamilton Valley, near Albury, at about 6:30pm on Monday.
He was last seen wearing blue boardshorts and a blue T-shirt and is believed to be on foot.
NSW Police Acting Inspector Troy Martin said Mr Trenchard-Harry was known to enjoy fishing and talking about it could help keep him calm until emergency services arrived.
Police, mounted officers, motorbike riders, bushwalkers, specialist dogs and an NSW police helicopter are involved in the search.
Acting Inspector Martin said Mr Trenchard- Harry's home backed onto bushland, but police did not know which direction he had taken.
"He could have gone into the bushland or he could have gone to the main road. We have no exact location at this stage," he said.
Mr Trenchard-Harry's parents raised the alarm after they were unable to find him on Monday night.
"We have a number of police with them at the moment and they're providing the family with support."
Residents around Centaur Road, Glenroy and Burrowes Road, as well as nearby parts of Albury, are being asked to check their properties, backyards, sheds, cars and caravans for any signs of Mr Trenchard-Harry.