Samin Tan, chairman of Bumi said the plan put forward by financier Nat Rothschild to revamp the board and remove 12 of the 14 directors would destroy value and lead to years of litigation.
"We should assume that if Nat wins this coming EGM, the discussion about the separation between Bakries and Bumi Plc will completely break down and as a result the Bakries will continue to be the shareholders of Bumi Plc," he told CNBC Europe's "Squawk Box".
"And what I can tell realistically is, it will be just months and months, if not years and years of litigation among various parties."
The split between the two shareholders, Nat Rothschild and the Bakrie family, has grown increasingly acrimonious after a series of high-profile disagreements at the London-listed miner since their union in 2010.
Tan, who joined the board and bought a stake from the Bakrie family said the Bakrie family was willing to separate from Bumi and hinted at a deal after the EGM.
"If this board wins the EGM, the relationship with Bakrie will be such that we can manage the Indonesian asset freely," he said.
"It's an extraordinary comment for the Chairman of a British public company to make," Rothschild responded in an interview on CNBC on Tuesday. "That seems to be the main thrust of his argument to win this EGM and it's wrong."