Footage has revealed bulldozers again clearing land on a property owned by the son of a man accused of shooting dead an environment officer in NSW's north last week.

Ian Robert Turnbull, 79, was charged with the murder of Glen Turner at Croppa Creek, north-east of Moree.

Turnbull was involved in a long-running dispute with the Environment Department over land clearing which had previously taken place in the region.

Mr Turner was in the area to respond to reports of illegal land clearing when he was allegedly killed by Turnbull.

The Land and Environment court last week ordered Ian Turnbull's son Grant Turnbull to begin remediation work on his property, known as 'Colorado', after his father pleaded guilty to illegally clearing over 400 hectares of native vegetation.

Since then, footage filmed by Tamworth-based ecologist Phil Spark and obtained by the ABC shows that on Monday this week, a bulldozer was again clearing land on 'Colorado'.

"I saw a dozer operating at Colorado, pushing up burning piles of timber in the area recently cleared," he said.

"Every additional impact is going to make remediation more difficult.

"The timber debris that's left after the clearing which they're burning now, that could have been habitat in the remediation area."

The ABC also understood bulldozers were operating at the property on Wednesday.

The Office of Environment suspended compliance operations in the area after Mr Turner's death, but said allegations of illegal clearing in the area were still being investigated.

Attempts were made to contact the owner of the property.