Data Protection regulators have sent out a strong warning to companies not to send out unsolicited marketing texts or emails, or make unsolicited marketing calls.

The warning comes as a number of companies pleaded guilty at the Dublin District Court this morning to carrying out such offences, which are breaches of Data Protection laws.

Under the law, companies may not send marketing emails or texts, or make marketing calls to individuals, unless those individuals have opted to receive them.

The texts and emails must also include a mechanism to easily allow people to unsubscribe. They can also only hold people's contact details on file for 12 months without renewing consent.

This morning at the Dublin District Court, Therapie Laser Clinics, trading as Therapie, with an address on Molesworth St in Dublin, pleaded guilty to four charges. Two related to the sending of unsolicited text messages to people, while the others related to those texts not having an opt out mechanism.

Assistant Data Commissioner, Tony Delaney, told the court that the company in question had failed to cooperate satisfactorily with the Data Protection Commission's investigation, that it had proven difficult to get responses from the company and that the company had previously received a formal warning from the Data Protection Commission.

Counsel for Therapie claimed the company took full responsibility for the issues before the court, and had taken steps to remedy the situation. But Judge John O'Neill it seemed the company had frustrated the Data Protection Commission at every turn. He convicted on two of the charges, and fined the company €4,000.

Separately, telecom company Carphone Warehouse, pleaded guilty to two charges of sending unsolicited marketing emails to customers.

It claimed it had obtained verbal in store consent from the parties, but this was disputed by the complainants and the company couldn't provide any evidence.

The court heard that the company had previously been warned about its data protection practices last year. It blamed the errors in these cases on human error during an email supplier changeover.

It said it had taken steps to ensure it won't happen again, and apologised to the court. Judge John O'Neill convicted the company on both charges and fined them €2,500.

In another case, telecoms company Meteor pleaded guilty to one charge of sending an unsolicited text message to a customer. The court heard that the message had been sent to up to 18,500 individuals who had opted out of receiving such marketing, because of a miscommunication between departments within the company.

Meteor apologised and said it had cooperated with the DPC's investigation and had taken steps to ensure it wouldn't happen again. Judge O'Neill expressed surprise that such a large company would not have had adequate systems in place to avoid such a difficulty. He gave Meteor two weeks to pay €5,000 to charity and said if this happened he would strike out the charge.

In the final case, mobile operator Hutchinson 3G Ireland, trading as 3, pleaded guilty to three charges of sending an unsolicited marketing text and email and making an unsolicited marketing call to individuals.

The court heard that the company blamed a coding error, a staff members acting not in accordance with rules, and a problem with an agent for the mistakes. The company apologised and said it had taken steps to ensure it didn't happen again.

Judge O'Neill ordered the company to pay €2,500 to charity in relation to the charge of sending an unsolicited text and said he would strike out the charge if that were paid. He also said he was taking account of the other two charges in making the decision.