Scott Quinnell says he was forced to leave Llanelli Scarlets after being "undermined" by Stradey Park officials.
Quinnell coached Llanelli RFC to Cup glory last year
The former Wales and Scarlets captain had signed a two-year deal to coach the region's youngsters and Llanelli's semi-professional Premiership side.
"I had every intention of taking up the position and had been working for two months to put a squad together," Quinnell, 33, told the Wales on Sunday.
"Unfortunately I wasn't allowed to recruit and keep the players I wanted."
Scarlets chief executive Stuart Gallacher refused to disclose the reasons behind Quinnell's shock departure last week.
Gallacher simply released a statement saying Quinnell had "had a change of heart and no longer wished to take up the appointment. This was accepted and we wish him every success in the future".
Quinnell had led Llanelli's Premiership team to the Konica Minolta Cup in 2005 before quitting to work for the family business.
His return to the fold seemed to be with a view to his being groomed to take charge of the Scarlets at some point in the future, but he has now set his sights of coaching elsewhere.
"I still want to build a career in coaching and I'm sad it cannot be at Llanelli," added Quinnell, who retired as a player last year.
"I am sorry to have left the players behind, but it is a great young squad and I wish them all the best for the future."
Paul Moriarty signed a new two-year deal as forwards coach at the west Wales region last week, while fitness coach Wayne Proctor and team manager Anthony Buchanan are also under contract.
There remains a vacancy for a backs coach, Gallacher saying it is not his decision but that he would like to see a southern hemisphere influence.