More lines of inquiry into the murder of a Japanese tourist are being explored by police after members of the public came forward with new information since a television show about the 20-year-old cold case aired.

Police revealed earlier this week they have a new suspect for the murder of Kayo Matsuzawa, whose decomposing body was found in a service closet of a central Auckland building in 1998.

Auckland police were alerted to the suspect by another policing district, but have remained tight-lipped over the person of interest.

The suspect had, however, used a bank card at a BNZ ATM machine on September 11, 1998, the day Matsuzawa went missing. Her naked body was found 10 days later - just metres away - dumped in an utility cupboard in the Centrecourt Building on Queen St.

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A new piece of evidence, DNA from an unknown man located under Matsuzawa's fingernails, has also come to light after further testing.

The entrance to the stairwell where Japanese tourist Kayo Matsuzawa's body was found in an utility cupboard. Photo / NZ Herald
The entrance to the stairwell where Japanese tourist Kayo Matsuzawa's body was found in an utility cupboard. Photo / NZ Herald

Today, Detective Inspector Scott Beard told the Herald police were also following other lines of inquiry from members of the public since Sunday night's episode of Cold Case on TVNZ.

"Investigations are continuing. However, there is a significant amount of work to do given the historic nature of the case," he said.

"Our team of investigators are working diligently to solve this case in the hope of bringing some sort of closure to Kayo's family."

Matsuzawa first came to New Zealand in 1997 to study English in Christchurch before, on September 11, she travelled to Auckland.

However, the 29-year-old was killed just hours after arriving in the city.

She had checked into the Queen Street Backpackers for three nights and at 2.14pm was filmed by CCTV cameras getting off a bus and crossing Queen St.

It is the last known sighting of the Japanese tourist alive.

Police found new DNA evidence underneath Kayo Matsuzawa's fingernails. Photo / Supplied
Police found new DNA evidence underneath Kayo Matsuzawa's fingernails. Photo / Supplied

Police were never able to determine her cause of death, but have said she was murdered.

And detectives have never commented in detail on the state of Matsuzawa's body, claiming there are things only they and the killer would know.

Police have also speculated Matsuzawa may have been drugged before she was killed.

Beard asked for anyone who believes they may have experienced similar drink spiking around the same time to contact police.

Information can be given provided on 0800 2653 2273.