Shadow minister Nick Thomas-Symonds said Dale Vince, a green energy entrepreneur, was a "legitimate person" to take money from.
Tory ministers have called for the donations to be returned, arguing it legitimises Just Stop Oil's tactics.
Protests by the environmental group, which wants the government to halt new licences for the exploration of oil and other fossil fuels in the UK, include blocking roads and disrupting sporting events.
Shadow international trade secretary Nick Thomas-Symonds said Labour had been "extremely clear on our views on Just Stop Oil". "What they are doing is entirely counterproductive and the only debate it's provoking is about our public order laws," he told BBC Radio 4's Today programme.
We spoke to Dale Vince about his support for Labour and the campaign group Just Stop Oil
Credit: Just Stop Oil/PA Wire