Residents in Northland's Dargaville should expect to see an increased police presence on Thursday amid an ongoing search for missing man Saxzin Steedman.

Steedman, 22, had been missing for three weeks, after last being seen leaving Cranley St on June 30 about 4pm.

He had not been heard from since.

Detective Senior Sergent Shane Pilmer, Northland CIB said there would be an increased police presence in Dargaville on Thursday as part of search efforts.

Police search and rescue teams and Land SAR would be focused on the Northern Wairoa Bridge area, he said.

The search involved specialist teams on foot, as well as a drone.

Saxzin Steedman is 22.

Angie Steedman / Facebook

"Unfortunately, Saxzin has not been found and police and his family continue to appeal for any information that could help us find him."

At the time he went missing, Steedman was believed to be wearing black pants, a black sweatshirt and red shoes.

"It is very unusual for Saxzin to not be in contact with anyone for this long, and police and his loved ones have serious concerns for his welfare."

Steedman's mother, Angie Steedman, told Stuff her son, who had autism, "wasn't in a good state of mind" before he disappeared.

She said she last saw him at Dargaville Hospital on June 30, believing he was due to be transferred to Whangārei Hospital. When she returned to the hospital the following day, she was told he had been discharged.

She was initially told her son had left the hospital on foot, but later learned he had been picked up.

She also said he disappeared without many of his essential belongings, including clothes, his wallet, car keys and a working phone.

In a social media post, Steedman said neither her son's phone nor his personal bank account have been accessed since his disappearance.

Anyone who had seen Steedman or knew his whereabouts or movements or who had any footage should call police on 105 and reference file number 260702/0678.

Information could also be provided anonymously through Crime Stoppers on 0800 555 111.