The Shadow Minister for Climate Change, Energy and Rural Affairs said she will not meet with Extinction Rebellion because of its action targeting newspapers.
Janet Finch-Saunders MS called the organisation "extremist and neo-fascist" after it targeted two News Corporation printing presses and delayed the delivery of Saturday newspapers.
The Conservative MS said: "Their actions in targeting a free press are beyond the bounds of acceptable political protest.
"Their actions are a dangerous example of hatred and intimidation which has no place in politics and I am also suggesting that all Welsh Conservative candidates for next year’s Welsh Parliament elections do not engage with them either."
Janet Finch-Saunders said she has the support of Welsh Conservatives leader Paul Davies. She said he has previously met with Extinction Rebellion but will not do so again.
The Extinction Rebellion movement needs to be de-legitimised and regarded as dangerous and criminal.
Extinction Rebellion has just completed five days of protests in Cardiff. Yesterday, activists took part in a socially distanced march from Cardiff City Hall to the Senedd. The group said it was protesting to call for "global social, racial, economic and climate justice".
On Thursday, the group protested outside the new BBC building in Cardiff city centre. It said it wanted to "highlight the fact that most media outlets are still falling short of explaining to audiences the gravity of the threat we face."