The platform is an instant messenger software app for mobile devices from a company located in the United States.
On April 7 last year, Mackey twice uploaded a video file of a child being abused - once through a chat group and also directly sending it to another user via a private chat message on the platform.
The summary said that any publication that "promotes or supports" the sexual exploitation of children or young persons is deemed an objectionable publication under the Films, Videos and Publications Classification Act 1993.
On April 19 the same year, Mackey uploaded another video through a chat group to the platform.
These publications were detected by the US-operated social media platform which filed reports with the National Centre for Missing and Exploited Children.
NZ Customs received a report from the US non-government agency about these offences in May 2021.
On July 21 last year Customs searched Mackey's home and seized 13 devices, including two iPhones, a laptop and Samsung M2 HDD.
Located in his iPhone Pro Max were 1639 objectionable files depicting the sexual exploitation of children, Customs said.
Mackey also had chat logs from an internet chat client for Windows.
While the chat logs were also not subject to charges, Customs said they provided evidence that Mackey was discussing child exploitation topics ranging from rape to incest.
There was also evidence of "several searches" to download child exploitative material.
When interviewed, Mackey confirmed he had used the social media platform account quag38m for more than five years.
He also admitted accessing child sexual exploitation material both while using the social media application and on the internet, and stated he knew the material was "bad".
Mackey pleaded guilty to six charges when he appeared in the Tauranga District Court on February 11.
He admitted two charges each of possession, distribution and exportation of objectionable publications.
The maximum penalty for both the possession and exporting charges is 10 years' prison for each offence and the distribution charges are 14 years' imprisonable offences.
Mackey's lawyer, Craig Tuck, urged Judge John Macdonald to allow his client to be remanded on bail pending sentencing to enable him time to organise his personal affairs.
Tuck said there was no risk that Mackey would fail to appear at his sentencing hearing and while the Crown sought a prison term he urged the judge to call for a home detention assessment.
Despite the Crown's opposition, Judge Macdonald further remanded Mackey on bail and called for a home detention report making no promises this was likely outcome.
The sentencing date for Mackey is yet to be confirmed.
