Former Whangārei mayor Stan Semenoff has been fined more than $15,500 and refused a discharge without conviction for permitting a large illegal rubbish fire at one of his business properties.

The fire on the morning of June 3, 2020, was at an industrial site owned by Semenoff and the Northland Trustee Limited on South End Ave, Raumanga.

A fire officer who attended said he saw black smoke billowing from five kilometres away and once at the site found a two-metre-high burning mound of rubbish including plastics, metal cable, PVC piping, iron, fenceposts, plywood, and tyres.

Enforcement officers from the Northland Regional Council accepted Semenoff was not directly responsible for the fire, which was lit in his absence by another employee - one of two managing his business for him while he recovered from a stroke.

But as managing director of the Semenoff Group he was personally charged by the council - on which he once represented ratepayers – with two breaches of the Resource Management Act (RMA).

One charge was for discharging or permitting the discharge of contaminants into the air from an industrial or trade premises by the burning of waste; the other was for discharging or permitting the discharge of contaminants into the air by burning tyres in breach of an RMA national environmental standard.

Each charge is punishable by up to two years in jail or a $300,000 fine.

Environment Court Judge Prudence Steven found him guilty earlier this year and in a remote hearing on Thursday fined him $15,520 and refused to discharge him without conviction.

Ninety per cent of the fine will go to the Northland Regional Council. Semenoff must also pay solicitors' costs and court costs ($130).

In setting the level of the fine, the judge took into account that the fire was a one-off and involved rubbish that was fly-tipped by the public at the previously vacant site, not rubbish related to Semenoff's daily business activities; the fire was not overly large and there was no lasting environmental impact; and Semenoff had since fenced off the site to guard against any future fly-tipping.

The judge acknowledged Semenoff's contribution to and standing in the community and his lack of previous convictions but said it only warranted a discount of 3 per cent to the $16,000 starting point of the fine.

Former Whangārei Mayor Stan Semenoff has been sentenced for air pollution caused by a large rubbish fire his staff lit. Photo / File.

At trial, counsel Matthew Atkinson argued that as former deputy chair of the Northland Regional Council, Semenoff knew the rules about lighting fires and would not break them.

Tyres from his businesses were routinely taken to the local waste management plant and processes were also in place for all other waste. Burning rubbish was not part of his business practice.

While Semenoff was back at work after his stroke, he was still relying on two key employees - accountant Carlo Lang and senior workshop manager Brett Borck - to make business decisions. It was Borck who lit the fire, Atkinson said.

Borck and Lang each gave evidence in support of Semenoff, Borck saying he removed rubber he noticed on the fire pile before lighting it and that he believed the fire was permitted as Lang cleared it with the Fire Service the week beforehand.

Lang said he thought the pile was purely vegetation and had not checked it. He supported Semenoff's view it was unnecessary to train the group's 120 or so employees on the subject of outdoor fires and that all had access to the regional council website if they needed information on the subject.

But at sentencing, Judge Steven said Semenoff's attitude to the possibility of an illegal fire at one of the group's sites was "risky" and "irresponsible" given the number of his employees and the past incidents. He placed too much emphasis on being on site himself to oversee day-to-day activities.

But if he was not there to micro-manage activities and in the absence of any other plan, the risk of an illegal fire was reasonably foreseeable, she said.

Judge Steven noted it was only after her guilty verdict - two years after the fire - that Semenoff finally schooled his staff on the subject of fires.

Atkinson's application for Semenoff to be discharged was on the grounds a conviction would cause significant damage to his reputation and legacy in the community, which would be out of all proportion to the gravity of the offending.

Refusing to grant the application, Steven said that was not a consequence she could take into account - there would always be a stigma attached to conviction and the fear of it would always be felt most strongly by those with local standing. She noted a conviction for RMA offending was for a regulatory lapse and did not have overtones of dishonesty, immorality or violence.