"For me, it is also good because in Japan I have family support."
Having had her high school education in Europe and the UK, the 42-year-old describes herself as "westernised" and says she considers New Zealand her home.
She named her son "Ao" meaning "cloud" in Māori - after Aotearoa, the Māori name for New Zealand.
"It has always been my intention to return to New Zealand to raise my son," Haruna said.
"His name is a strong connection and a reflection of my attention."
Haruna's husband, an established architect in Osaka, will remain in Japan to work because he would find it difficult to find any type of employment in New Zealand that could match his earnings.
Despite being named after New Zealand, Ao's application for residence under the family dependent child category was declined by Immigration New Zealand (INZ).
In a letter to Haruna, the agency said her decision to remain in Japan after her birth meant she "was not living permanently in New Zealand in line with immigration instructions".
It said also that Haruna did not satisfactorily provide evidence to show "current and future commitment to New Zealand by way of employment and tenancy/home ownership".
The agency said in the same letter that the 4-year-old did not meet the requirements for any other residence category.
As a visitor visa allowed Ao to be in New Zealand only for three months each time, Haruna has been shuttling between Japan and Auckland for the past year.
Haruna said she wanted to enrol for a course in university and find employment, but that it's impossible because of the immigration status of her son.
"My life has been put on hold and in limbo because of this," Haruna said.
"How do I take on anything permanent when I am not sure if Ao can remain here long-term?"
INZ manager Michael Carley said Ao's application was declined principally because Haruna was not living permanently in New Zealand.
"It was assessed that Ms Haruna has not satisfactorily provided evidence to show her current and future commitment to live permanently in New Zealand," Carley said.
"Ms Haruna was living outside New Zealand between April 2013 and January 2016 and since then has spent a considerable amount of time outside New Zealand."
Carley said as a Japanese citizen, Ao was able to travel and remain for three months under visitor waiver provisions.
"Should however Ms Haruna wish for her son to remain in NZ with her for a longer period there is a specific visitor visa category that allows up to two years' stay for children of New Zealand residents," said Carley.
"This would be sufficient time for Ms Haruna to move to New Zealand with her son and for a residence application for him to be processed."