Grieving and stressed, the father of baby Ihaka Stokes says he is "happy they have finally arrested somebody" for the alleged murder of his child.

Police have charged a 22-year-old man with murder during the 13th day of an investigation into the 14-month-old's death in Christchurch.

Detective Senior Sergeant Mike Ford said the man – who was known to Ihaka – had been arrested and would appear in Christchurch District Court on Thursday. For "legal reasons" police could not identify him.

SUPPLIED Police have arrested a 22-year-old man over the death of 14-month-old Ihaka Stokes

Ihaka's biological father, Cameron Ellen, 23, said he and his family welcomed the news after a tumultuous fortnight. Police had informed him via a phone call.

"It's definitely been stressful, that's for sure, and not knowing who to believe and all of that, it's just a little bit crazy".

READ MORE: Ihaka 'would have made an amazing big brother'

Ihaka was taken from his Truman Rd home in Bryndwr to Christchurch Hospital about 10:40pm on July 3 with multiple blunt force fractures and other non-accidental injuries inflicted in an "extremely violent" assault or assaults, police said.

He died shortly after arriving at hospital.

Ellen, who helped carry his son's small white coffin to the hearse alongside Ihaka's maternal grandfather Paul Stokes at an emotional funeral on Friday, said he hoped the arrest would end speculation, particularly on social media.

Ellen said he had had limited and occasional contact with his son. He had been in an "on-and-off" relationship with Ihaka's heavily pregnant mother Mikala Stokes, 19, before they split last year.

He did not know what would happen with the second child, which is due within weeks.

Ellen said he would not attend the court appearance on Thursday because he had left Christchurch for Kaikoura for a few days "to get away from it [all]".

"Going to the mall, I've had people sit down beside me and realise who I am and get up and walk away, people staring and pointing. It got to the point where I left the mall because I didn't want to be there any more."

Ford said police had spoken to more than 42 witnesses as part of Operation Truman. Most were co-operative, while some were unwilling to speak.

Seven full-time investigators would continue to work "tirelessly" on the case "to ascertain why a typical day ended so tragically for Ihaka", he said.

"Canterbury police investigations will continue to focus on the events which led to Ihaka being taken to hospital," he said.

At Ihaka's funeral, Mikala Stokesspoke of the pain in losing her first child.

"Even though you are not here physically, I know you're going to do everything to be the best big brother ever," she said.

"I've never met someone as stubborn or cheeky as you. You knew what you wanted, when you wanted it and how you wanted it. There were no ifs, buts or maybes about it."

The following day, Marrisa Hunton, Ihaka's aunt and Stokes' sister, said the death was an accident and not a result of foul play.

"The important thing is that the family knows the truth," she said.