The incident is believed to have happened in the early hours of morning and the video appears to show both people under the influence of alcohol or drugs.
National director of Family First Bob McCoskrie told the Herald there was a time and place for sexual activity but not in public, and "definitely not where families and children are passing by".
"This couple are showing complete disrespect for both themselves and for the general public. Families should definitely report this type of behaviour to the police. Public indecency is still - and should be - a crime."
NZ Police were approached for comment and said they hoped people would notify the police rather than just taking a video.
"Police encourage anyone who witnesses offensive behaviour to report it to their local Police," a spokesperson said.
"We take all reports of this nature seriously, and investigate appropriately."
Alcohol Healthwatch spokeswoman Nicki Jackson said Kiwis had a growing problem with drinking.
"This time of the year our police and hospital resources are stretched to the limit to cope with this silly season. We all need to be part of an urgent cultural change by supporting our friends and family to have alcohol-free days and to limit the number of drinks they consume."
She called on people to be extra vigilant around how drinking was modelled in front of children.
"Also, keep in mind that alcohol is the most harmful drug in society; our drinking culture shouldn't be the main source of entertainment on social media. By taking these actions, our over-burdened police and ED staff can have some well-deserved time off."
Last week, a group of young men filmed naked woman in a Parnell carpark while under the influence of drugs.
As a result, members of the public have been ridiculing the group for filming the woman instead of trying to help her.
McCoskrie said it appeared that the distressed and incapacitated woman in the video needed practical help, not a social media campaign.
"It's disappointing that the public didn't call for help and didn't offer help if, and where, possible."