The street is close to multiple schools including primary, intermediate, and colleges.
As school children and other pedestrians walked past, the man performed an indecent act in his car, filming himself as well as the reactions of the passersby.
He has also admitted another charge of performing an indecent act near Petone Beach.
In that incident, he was reported by a passing runner.
Police carried out a search warrant at the hotel room the man was staying in on June 18, and found 10 rounds of .22 calibre ammunition.
He does not hold a New Zealand firearms licence.
When police spoke to the man, he told them he was on drugs the day of the indecent act near the schools, and did not remember doing it.
In court today, the man's lawyer applied for interim name suppression on the basis publication of his name would cause extreme hardship to his father, who has a terminal illness and is not expected to survive the month.
She said while the man's father knew about the offending, it would be a further layer of distress if he were to see his son's name published, and argued it could cause his health to further deteriorate.
She said she was "unlikely" to apply for permanent name suppression at the man's sentencing in October.