Announcing his decision in a lengthy post on his Facebook profile, Koprivnikar said the "premeditated media and political smear campaign" against him had achieved its purpose and that the cooperation he was looking forward to was turning into tilting at windmills.

"I was genuinely happy to receive the invitation to join BTC, firmly convinced that with no act of mine whatsoever have I raised the slightest doubt as to the honesty and lawfulness of my actions," Koprivnikar said in the post in a reference to the job at operator of Slovenia's largest shopping district.

"I have renounced the ex-politician's allowance, looking for a job with the state administration or with any company liked to the state in any way in order not to raise any doubt. I've obviously fell victim to my own naivety," Koprivnikar said.

Media alleged that he had preparing ground for years to get the job with BTC, including through legislative changes that would eventually see the Agency for Communication Networks and Services (AKOS) award a licence to test G5 wireless technology to BTC.

Denying the allegations, Koprivnikar said he has made himself available to all oversight and law enforcement institutions, as well as political bodies to provide any information or explanations required, but he decided to present them via Facebook because he feared few were interested in facts.

He said that preliminary G5 frequency testing had been planned based on the European Commission's action plan for 2017 and 2018 and that the projects were to last three years. He noted that apart from BTC frequencies for testing had also been granted to three other companies.

He also said that there had been no complaints or remarks in the legislative process against the electronic communications act provision pertaining to the award of free temporary testing frequencies.

Confirming that Koprivnikar was quitting the job, BTC said it had notified AKOS it was returning the temporary test frequencies and would not use them and had not used them yet.

"Despite the fact that they were intended for testing, non-commercial and non-profit purposes solely in the BTC City area, the company is returning the frequencies in light of the negative political and media reactions," BTC chairman Jože Mermal said in a written statement.

The allegations of abuse of office prompted AKOS on Monday to review the procedure to award the licences to test G5 mobile services. This was despite AKOS denying the allegations of wrongdoing in the procedure.

The issue will also be discussed tomorrow by the parliamentary Public Finance Oversight Commission.