Ozbey, 26, abandoned East Bengal after two years as their highest goalscorer, notching up 35 goals in 48 games since joining the I-League side in 2010.

He's now joined their Old Firm-style rivals Mohun Bagan, who play out of the same 120,000-capacity stadium in Kolkata as East Bengal, on a two year deal worth a reported 30 million rupees (about $520,000).

His old club immediately lodged a protest with the Indian FA, claiming the former Blacktown City striker had accepted an advance money voucher from them, tying him to the club.

They refused to release his player token, preventing him from joining his new team-mates.

Today the IFA ruled that Ozbey had breached the rules and docked him a month's wages, worth around $18,000, and fined him a further $8,500-plus.

They also ordered him to write a letter to say sorry to East Bengal who would then release his player token once they received the apology.

The two clubs have a bitter rivalry dating back to the 1920s, and it remains the most fiercely fought derby in the five-year old I-League.

East Bengal - coached by Englishman Trevor Morgan - were last year's I-League runners-up, but Mohun Bagan have the edge in derby clashes, winning five to East Bengal's two, with three draws.

Mohun Bagan general secretary Anjan Mitra welcomed the end of the row to allow the Australian to move on and begin work with his new club.

"It's really harsh and tough on him," Mitra told The Times Of India. "But we want to sort this out so that he can play for us without any hassles."

An East Bengal official added: "The decision proves that we were right. It's a moral victory for us."