He has been charged with assault with intent to rob with a firearm, which carries of maximum penalty of 14 years in prison.
Detective sergeant Barry Bysouth said investigations were ongoing and there were a number of other people police still wanted to interview.
"There are a number of other leads we're following and other people we need to talk to.
"From a police point of view, our aim for the community is to prevent any kind of criminal offending.
"Offending of this nature, with a firearm against members of the public, is extremely serious and our response to this particular type of crime is proportionate to the level of violence used during the commission of the offence."
Mr Bysouth said the firearm, police believe was a single barrel sawn-off shotgun, was yet to be recovered.
Rongonui will appear in Napier District Court on December 11.