Oliseh had claimed that he was suspended because he refused to partake in fraud.
After he was suspended on Wednesday, February 14, Oliseh claimed that he was taken off his position as head coach because of his refusal to participate in illegal activities and violate the law.
“I confirm: Due to my refusal to participate in Illegal activities at Fortuna Sittard and violate the Law, I have been Suspended from my duties as Coach by the Foreign Owners of Fortuna,” Oliseh wrote on Twitter.
“Unfortunate for the lovely fans, my players and our hard-fought phenomenal positioning for promotion.”
The club on Thursday, February 15 have reacted by revealing that they will be taking legal actions against the Nigerian coach.
“Fortuna Sittard has taken note of the unsubstantiated allegations made yesterday in various media by Sunday Oliseh after being on non-active earlier that day,” the club said in a statement on their website.
“Although Fortuna Sittard does not wish to go along with accusations in the press, Fortuna wants to fight the accusations made.
“In this context, the club will also take the necessary legal follow-up steps. Fortuna does not recognize itself at all in these accusations, which were not previously ventilated by Sunday Oliseh internally.
“Something that can be expected in view of the seriousness of the accusations regarding alleged illegal practices. Fortuna Sittard chooses to respond once by means of this statement because many media have turned to her immediately after the accusations made to the club's address.”
The club further revealed that the decision to suspend Oliseh wasn’t made overnight.
“The countless clandestine acts, as well as the disrupted employment relationship on the part of Sunday Oliseh, have unfortunately led Fortuna to make him non-active,” the Eerste Divisie club said.
According to Fortuna Sittard, they will further reveal the culpable behaviours that led to the suspension of Oliseh during the legal proceedings.
“Fortuna Sittard has received numerous written statements from individuals who have pointed to various culpable acts that will also be introduced during the procedure,” the club said.
“Many of them explicitly indicated that they no longer wanted to cooperate with Sunday Oliseh. Fortuna Sittard has therefore consciously opted to preserve the peace and to resolve the escalations as much as possible internally, also with the help of external help.”
Oliseh was appointed coach of Sittard in December 2016 with the club on the verge of relegation from the Eerste Divisie, the second-highest tier of football in the Netherlands.
The former Super Eagles coach has improved Sittard’s results remarkably and after avoiding relegation last season went on to win the Second Period title in January 2018, their first title in 21 years.
Sittard are currently third on 44 points in the league table, five points behind leaders NEC and have already secured qualification to the playoffs for the promotion to the Eredivisie.
However, the team has declined in recent weeks and have gone on a four-game losing run.
Claudio Braga, a Portuguese has been appointed to replace Oliseh in the interim. He will be assisted by Kevin Hofland, a former Dutch defender.