Western Australian Premier Roger Cook claimed on Tuesday that it was "irresponsible" and "inappropriate" for the former CEO of an Aboriginal corporation to allegedly attempt to leverage new heritage laws in pursuit of a share of millions of dollars in grant funding for the organisation.

Former Whadjuk Aboriginal Corporation chief executive David Collard left the organisation after revelations that he allegedly flagged withholding approvals under the new Aboriginal Cultural Heritage Act until the organisation received a quarter of a $10 million Commonwealth grant for restoration of the Canning River system.

On Monday the corporation told National Indigenous Times that "the employment relationship with Mr Collard ended in July 2023 and this was not related to the Canning River planting".

The corporation said in an earlier statement that the rescheduling of the Canning River tree planting project was not related to the Aboriginal Cultural Heritage Act.

The South East Regional Centre for Urban Landcare (SERCUL) was aware of Mr Collard's alleged position, which they said had been relayed by a Department of Biodiversity, Conservation and Attractions officer, when making the decision on Friday to postpone the planting of 5,500 shrubs and trees along the banks of the river at the weekend.

More than 100 volunteers prepared to take part in two separate tree plantings were informed in an email from SERCUL the events were not going ahead because of "sudden problems surrounding the new Aboriginal Cultural Heritage Act".

Mr Cook said the dispute was a "fight over Federal government funding" and had "nothing to do with Aboriginal cultural heritage".

"It's irresponsible. It's inappropriate," he told The West Australian.

"From time to time, you see people will use some law to try to bully people or to get a particular outcome. That's not the fault of the laws. That's the fault of the person that's undertaken those behaviours."

Aboriginal Affairs Minister Tony Buti, who telephoned SERCUL and a number of southern council mayors to explain the situation, said on Monday no one had the power to cancel a tree planting event, which is a low-level activity and does not need a permit.

Dr Buti described the cancelled tree planting as an "isolated instance" that had come about as a result of a "rogue individual".

Mr Collard told The West Australian that misinformation was "being bandied around at the moment".

"I will not put up with any of this," he said.

On Sunday City of Canning Mayor Patrick Hall said: "We're standing here today in solidarity with some of these environmental groups saying, somebody needs to clarify this legislation — it has become somewhat of a mess."