The woman was taken to hospital in a serious but stable condition and the child received minor injuries, Crawford said.
“Both are understandably shaken. There is no place for this sort of violent behaviour in our community.”
The arrest was a great result after a “terrifying ordeal for the victims”, Crawford said.
“I’m pleased we have been able to arrest this man and hold him to account.”
Police had since found a firearm and property believed to be from the victims’ address, he said.
A 38-year-old man remained in custody, with charges pending.
Police want to hear from anyone who witnessed the incident on Williams Ave, or any sightings of a yellow Suzuki Swift travelling west on State Highway 12 towards Whirinaki, Kouto Loop Rd and then Ōpononi and Ōmāpere.
They were also seeking sightings of a male acting suspiciously in the Ōmāpere area on Thursday morning, Crawford said.
“Anyone who can assist our inquiries is asked to get in touch. Information can be provided online at 105.police.govt.nz, or by calling 105. Please use the reference number 260820/5258.”
Information could also be given anonymously through Crime Stoppers by calling 0800 555 111.