Banks has not responded to Herald requests for comment. He made no appearance at this morning's hearing and was not represented by lawyers.
The court heard Shaw's legal team, headed by Lowndes litigation partner Jacque Lethbridge, had encountered difficulties in serving documents on Banks, who they say has not engaged in attempts to resolve the claim.
Justice Tim Brewer made an order allowing Shaw's legal team to serve documents on a solicitor linked to Banks in future, rather than personally serving him with documents.
He scheduled the next hearing date for June 29.
Brewer made the point that if Banks had been unaware of today's hearing, media coverage since the story broke in this morning's Herald meant the two-time Auckland mayor would now "know what's going on".
He added that a full High Court paternity proceeding would bring enormous costs. This could be prevented by a simple DNA test which could conclusively rule out Banks as being Shaw's birth parent.
"There's some suggestion that Mr Banks doesn't want to have a DNA test?," he asked Lethbridge.
She replied that there had been attempts to have Banks engage on the question of whether he was Shaw's father, and that a DNA test could ultimately eliminate him from any paternity claim.
"The evidence is that he didn't engage in that."
Shaw, who is based overseas and did not attend this morning's hearing, is seeking a court declaration of paternity.
The court action follows years of uncertainty around the identity of his real father.
Though a DNA test could conclusively eliminate Banks as Shaw's blood relation, people cannot be compelled to provide DNA evidence in paternity cases and Shaw is not seeking any such order from the court.
Shaw, an English language teacher who now lives in Japan with his wife Noriko and son Kent, says the case is not about money. He simply wants certainty about his ancestry for him and his family.
Outside court, Lethbridge said if Banks refused to take a DNA test it would result in huge costs for all parties.
"[Shaw] learned for the first time that Mr Banks was most likely his father in 1999 and he's been trying to establish that ever since.
"I can confirm that my client has either personally or through family members tried to have this matter clarified with Mr Banks but that has been unsuccessful.
"Most reasonable people faced with this scenario ... would probably try and get to the bottom of it without the need for putting people through the cost of a High Court proceeding and the embarrassment that might follow."
Banks refused to comment or say whether he would take a DNA test when approached by the Herald today in Remuera.
In an earlier statement, Lethbridge said the case was not about money, but about certainty over paternity.
"Mr Shaw wishes to have the details of his biological father recorded on his birth certificate - which details at this stage remain blank - and for his son to know who his paternal grandfather is with certainty."
She added that taking court action against Banks had been a "harrowing and difficult experience" for her client.
"Mr Shaw feels he has been left with no option other than to pursue the matter through the courts."
Banks is a former National Party Cabinet minister and two-term Auckland mayor. He was convicted of filing a false electoral return in 2014 in connection with a donation from Kim Dotcom. However he was subsequently acquitted after new evidence came to light.
Banks is married though separated from his wife Amanda. The couple have three adopted children.
Shaw attended Mt Albert Grammar and grew up believing his mother's Asian partner was his father.
His mother is alleged to have had relationship with Banks in the late 1960s while working as a nurse in Hamilton.
She eventually told Shaw about his parentage in 1999 and he tried to meet Banks in the early 2000s during a trip home from Japan to ask the then mayor "are you my father", a 2001 women's magazine article alleged.
The meeting never happened, culminating in today's court proceedings.
Otago University law professor Mark Henaghan told the Herald paternity cases like this were rare.
They were more usually taken by women under the Family Proceedings Act for child support purposes.
Henaghan said applicants would need to produce strong circumstantial evidence to prove the two parents had been in a relationship at the relevant time, often in the form of sworn affidavits and photographs.
DNA tests could conclusively eliminate someone from paternity. And though a person could not be compelled to take a DNA test, a court could draw "adverse inferences" if they refused.
Establishing paternity was important for some people for identity purposes, and others for their genetic lineage, Henaghan said.
But a paternity declaration also had important legal implications.
"They are your legal father. They become your next of kin, there's all sorts of things that come into play. There are potential claims under the will. So it does have legal ramifications."
