Smuts in his spare time is a director of the Landmark Foundation, an environmental and conservation NGO.

He has been at loggerheads with the provincial government over the issuing of permits to farmers to hunt predators such as jackals and caracals. He dubbed the traps for the predators "Zille slaughter irons" .

He characterised the provincial department of environmental affairs' attempts to force Cape Nature officials to approve the cull as "kragdadig" (bulldozed through).

Smuts, a senior manager at the Riversdale Hospital, was told in a letter from the provincial health department's labour relations unit that his "conduct is in direct conflict and unbecoming of an employee of the [Western Cape government]".

The province's head of health, Craig Househam, said yesterday: "He's a public servant and there's an employee/employer relationship that he has to take into account."

Denying that the letter was an attempt to muzzle Smuts, Househam said he could raise concerns but had to change the way in which he did so. Smuts said his work with the Landmark Foundation was secured in his contract with the provincial department of health, and he would continue his criticism of the cull.