She is charged with wounding Tongia with intent to cause grievous bodily harm and being party to his murder.
A 19-year-old man was charged with being an accessory to murder three days ago.
Two of the women appearing in the High Court today were earlier charged with murdering Tongia - Weston and the 35-year-old. Weston was also charged with assaulting Tongia with a knife earlier in the night.
Colvin was charged with being an accessory after the fact to the murder.
At her first appearance in January, she grinned and mouthed words to her supporters as she stood in the dock at the Wellington District Court on January 21.
Court documents allege she "actively suppressed evidence" by hiding a firearm at an associate's property to help someone avoid conviction.
Police revealed in January they had found a firearm during a search in Wilton that they believed was linked to Tongia's death.
It is being forensically analysed.
Police said they are also looking into whether the weapon is linked to other offending across the district.
In late January, Wellington field crime manager Detective Inspector Darrell Harpur foreshadowed that more arrests would be coming after police charged the 24-year-old woman.
"This is the third arrest we have made in relation to the death of Mr Tongia, and while the primary offenders have now been charged, I am confident it won't be the last," he said.
Last month, police extended their sympathies to Tongia's loved ones.
"I want to acknowledge the investigation team who worked tirelessly on this very complex case, and commend them on their professionalism and dedication to holding those involved to account. They worked long hours and took valuable time away from family throughout the holiday period to ensure justice was done for Rau Tongia."
The public gallery in the High Court at Wellington was packed with people this morning, with yelling breaking out between two separate groups at the end of the hearing.
Some called Weston a "mongrel" as she was led from the court, while others waved to Colvin, who appeared by audio visual link.
The other woman also appeared by audio visual link.
Their lawyers entered not guilty pleas on their behalf, and they were remanded in custody.
Colvin has also made a bail application, which Justice Francis Cooke will make a decision on later today.
A trial date has been set for May next year, with the trial set down to take six weeks.
The 27-year-old charged who appeared in the Wellington District Court this morning was remanded without plea to appear in court again in March.
She was granted interim name suppression.
Her charging document states she was party to the murder of Tongia by providing the vehicle used for the offence.
