Super League's new chief executive Robert Elstone is facing a potential civil war just eight days after taking office.
Details of next season's structure were revealed as the Super 8s are set to be scrapped but the Million Pound Game will stay and be contested by the top two Championship clubs.
Lenagan also denied claims that Super League's attempt to be more in control of their own destiny- which included the appointment of Elstone - was not a breakaway from the RFL, and said no matter what changes are made for 2019 the funding given to the lower leagues will be unaffected until at least the end of the broadcast deal which runs to 2021.
His remarks prompted a fierce response from Hetherington who, in a statement, said: "Today's announcement regarding plans for next season appear to be an absurd grab for power for the game by a small group of men who think they own the game".
'Leeds Rhinos are not party to this and are totally against the creation of a separate Super League executive.
'The game is in need of strong leadership from (chairman) Brian Barwick and his board of directors at the Rugby Football League and this announcement should bring a response from everyone connected with the game'.
Elstone was appointed by the Super League clubs following an extra general meeting last October when they voted Rugby Football League chief executive Nigel Wood off the board.
"We are committed to promotion and relegation", the Wigan owner, Ian Lenagan said.
"What we have done is taken responsibility for commercial activity to give the top tier the focus it should have".
The former Everton chief executive spoke of his passion for rugby league at today's media conference in Warrington.
"This is the only job that would have taken me away from Everton", he said.
"We believe it is very important that the sole focus is on Super League". "I've loved rugby league from the first day I can remember".
'Do not be misled by any conclusion that the format for 2019 has been decided, ' Nicholas said.
Elstone says he needs the support of Hetherington and is hoping to persuade him to drop his opposition.
"We believe this was disrespectful to the present consultation process involving the RFL and Championship/League 1 representatives where we are nowhere near a conclusion".