is managed through the fact that I absolutely abstain from being part of that conversation," she told the ABC.

"For instance, if COTS is on the agenda, I typically leave the room or I definitely don't participate in that conversation."

Margie McKenzie says she has managed potential conflicts by declaring all her interests. ( ABC News: Michael Slezak )

But documents obtained by the ABC under freedom of information laws show Ms McKenzie failed to declare her interest in Gempearl at board meetings for the first two years she was on the board of the authority.

At a board meeting in 2015, the documents show Ms McKenzie "clarified" her declaration, and amended it to include that she was the managing director of Gempearl.

"I originally didn't think it was required. A change indeclaration forms spurred me to include it at this time," Ms McKenzie told the ABC.

But Ms McKenzie has never declared her husband's interest in the Reef and Rainforest Research Centre Ltd, or her husband's interest in Gempearl.

Asked about this, she said: "I do not believe it to be required, it's my declaration, not Col's."

Questions over the effectiveness of culling method

Crown-of-thorns starfish are currently killed one by one. ( Supplied: Lisa Boström-Einarsson )

The control of crown-of-thorns starfish has been a priority for successive governments and the Great Barrier Reef Marine Park Authority.

The starfish are considered by some experts as the second biggest driver of coral loss — and were the single biggest driver before the unprecedented bleaching hit the reef in 2016 and 2017.

The money being spent on killing