Evangelos Marinakis, the new Nottingham Forest owner, denies accusations of match-fixing and insists he intends to restore the two-times European Cup winners to the Premier League after his £50m takeover was completed on Thursday.

Marinakis, the shipping magnate who also owns the Greek champions Olympiakos, has passed the EFL owners’ and directors’ test and his NF Football Investments will now be permitted to purchase 100% of the club’s shares from the previous owner, Fawaz al-Hasawi.

Uefa confirmed this week that it is still monitoring allegations from last year that the 49-year-old was involved in match-fixing in his homeland but, speaking to the BBC, Marinakis said that allegations he is involved in a “criminal organisation” were invented by “jealous” opponents to “destroy” his success with the Greek champions.

He said: “I have nothing to be afraid of and to worry about as I have done nothing wrong. All these years, a lot has been said but nothing came out in reality. All of it has been dismissed and we have been clear from all of this.

“ Now there is a last case remaining – there are about 80 persons involved. I can tell you again that I have nothing to do with it because I know very well what I have done and how I have achieved victories. Of course I cannot stop our opponents talking or bad-mouthing.”

His takeover of Forest, who narrowly avoided relegation to League One by defeating Ipswich Town on the final day of the season, brings to an end more than a year of negotiations that also saw an attempted purchase of the club by an American consortium led by the businessman John Jay Moores. Marinakis, who moved to Watford as a 15-year-old and attended university in the UK, has guaranteed the future of the manager, Mark Warburton, and vowed to reward supporters for their loyalty to the club that last played Premier League football in 1999.

“We have a long-term plan and within this long-term plan we want to bring Nottingham to where it belongs,” he said. “And of course Nottingham belongs in the Premier League. And Nottingham belongs to the elite of the Premier League. Furthermore, the supporters of Nottingham have been tired all these years, they didn’t have such good times. But they remained loyal and for us that’s very important.

“ The potential is huge. The potential of this team is that when it will be very well organised, when it will achieve victories again, when it will have a better position in the Championship, when it will have a better position and we can look seriously at the Premier League, then we will be there to stay.”

Nicholas Randall QC is set to take over as chairman, while Ioannis Vrentzos – who worked under Marinakis at Olympiakos – is Forest’s new chief executive.