The man who died from toxic fumes in a central Auckland hotel room had failed to attend a court hearing over fraud charges earlier in the day.

Mark Lawrence Ivil, 58, had been accused of living off others' fortunes for decades to the tune of $4.28 million and was facing numerous charges laid by the Serious Fraud Office (SFO).

He was put through decontamination treatment by fire crews outside the Grand Hotel Chancellor on Hobson St but died at the scene early Tuesday afternoon.

JASON DORDAY & RORY O'SULLIVAN/Stuff.co.nz One man has been confirmed dead following a toxic leak at the Grand Chancellor Hotel in central Auckland.

Police said his death was not being treated as suspicious.

SFO spokeswoman Andrea Linton said the situation was a tragedy for Ivil's family and that no further comment would be made.

However, she confirmed Ivil had been due in Auckland District Court on Tuesday morning but had failed to attend.

JASON DORDAY/FAIRFAX NZ One man is dead following an incident involving a harmful substance at an Auckland hotel.

Announcing the charges in July, SFO director Julie Read said Ivil had "a reputation for being elusive and using aliases".

The SFO laid 21 charges of obtaining by deception, 14 charges of obtaining by false pretence, two charges of using a forged document and two charges of obstructing an investigation.

It alleged Ivil persuaded people to give him money with "convincing and plausible scenarios" about returns on a property development in Australia as well as other schemes.

@bigrichNZ/TWITTER Emergency services are decontaminating an inner-city Auckland hotel after receiving reports of a toxic smell.

Ivil appeared in Tauranga District Court last month but the case had recently been transferred to Auckland.

Rotorua lawyer Murray McKechnie had previously acted for Ivil but refused to confirm if he was still Ivil's lawyer when contacted. "I have no further comment to make," he said, before hanging up.

Ivil is understood to be the brother of developer Brent Ivil whose company West Harbour Holdings collapsed into liquidation in March 2013 owing at least $3m.

READ MORE:

* Fraud accused Mark Ivil makes no plea

* Ivil accused of defrauding others of $4.28 million

A number of staff and guests were evacuated from the hotel and St John ambulance staff assessed 10 patients at the scene who did not need to be taken to hospital.

Fire Service assistant area commander Dave Woon said it was too early to say whether it was a drug making operation.

He said he was unsure what chemicals were used but that a number of different chemicals had been combined together.

The mixed chemicals formed a "gas that you would typically find in Rotorua. A rotten egg smell".

Woon said it was a rare situation and he had never seen anything quite like it.

He said police were now leading the investigation and were carrying out "significant testing and identification processes".

There were unconfirmed reports that the chemical involved was hydrogen sulfide.

More than a dozen emergency service vehicles had blocked off two lanes of Hobson St before the street, and the hotel, were reopened about 1.45pm.

The call about the "toxic smell" coming from a bathroom in a room on the third floor of the hotel came at about 11am, Fire Service shift manager Dallas Ramsay said.

Fire crews carried out an evacuation and removed the 58-year-old man from the room where the smell originated.

It was understood the smell coming from the hotel room was consistent with that of the chemical and the Fire Service had been carrying out chemical tests at the scene.

Staff said the gas stunk out two floors of the hotel.

One staff member, who asked not to be named, said she noticed the stench in the morning, which was like "sewage".

"It started from the third floor and once you got out of the lift on the second floor you could notice it. It was so strong."

The worker said she was among about eight employees evacuated from the building and only found out later from firefighters that it was a toxic gas.

Ramsay said the Hotel Grand Chancellor had been cordoned off while decontamination was carried out.

A hazardous materials unit and 11 fire trucks were at the scene, along with police and ambulance crews, she said.

Police advised motorists to avoid lower Hobson St as two lanes on the street had been closed due to the incident.

Grand Hotels International, the owner of the Grand Chancellor Hotel, said everybody in the building had been evacuated.

Grand Hotels International marketing manager Hazel Rigler said the hotel had not been told when staff and guests would be able to re-enter the building.

As far as the hotel was aware no staff had been harmed in the incident.

Rigler said she could not comment further about what had happened, adding that the incident was being dealt with by emergency services.