A company that leases offices from a property firm run by presidential candidate Seán Gallagher has claimed Mr Gallagher threatened to close the building and demolish it if the company took his firm to court.

The dispute between the tenant, Nokia Ireland, and Mr Gallagher's firm, Clyde Real Estate Limited, was before the High Court today.

It relates to the provision of heating and air conditioning in a premises in Blanchardstown in Dublin, owned by Clyde Real Estate, of which Mr Gallagher is chief executive officer.

Mr Gallagher denies making threats and says he was informing Nokia that if fire safety works had to be stopped because of court proceedings, the building would have to be closed.

Mr Justice Tony O'Connor said the dispute, which Nokia says has health and safety implications for more than 100 employees, was "quite a serious situation" and he encouraged the parties to sit down together.

Nokia Ireland claims Clyde is in breach of a 2015 lease agreement to provide heating, ventilation and air conditioning, and has sought injunctions preventing the company from demolishing or decommissioning the current system providing those services.

It wants Clyde to provide the services in accordance with the terms of the lease.

Clyde says Nokia is trying to force it to operate an obsolete system.

The matter was first before the court in June but was adjourned until today after Clyde gave undertakings in relation to the matter.

The court was told temperatures in the offices used by Nokia, rose to 27 degrees during the heatwave in June and July.

Barrister Imogen McGrath said there was now concern that temperatures in the premises would plummet in colder weather.

She said there was an offer to put in a replacement system by January of next year but that this was not sufficient.

Ms McGrath said Mr Gallagher had threatened by email in June that the building would be closed and demolished if Nokia sought an injunction.

However, Mr Gallagher claims he was simply informing Nokia that the architects and builders engaged in works on the site would pull out and move on to other jobs, if that work was going to be held up by legal proceedings and, in such a situation, the building would not be compliant with fire safety regulations and would have to close.

The company says it is not in breach of its lease.

It says the HVAC system, which has been providing air conditioning and heating, is beyond its working life, is hugely problematic, totally inefficient, time consuming, expensive to repair and maintain and needs to be replaced.

It also says it has taken every step to try to agree a way forward.

Barrister John Freeman said Nokia acknowledged this two years ago and was trying to force Clyde to operate an old, obsolete system.

The case will be back before the court on 27 November.