Tim Eggar, minister of state at the DTI, hit out at the pressure group's tactics in a filmed interview with BBC TV, most of which will not be shown.
A transcript suggests that if single-issue groups like Greenpeace managed to frustrate the will of ministers, the Government could opt out of international agreements and act unilaterally.
Mr Eggar said Greenpeace's ability to humble one of Europe's biggest companies (Shell) was "inappropriate, very dangerous. I think the advent of single-issue politics, using what one can only describe as unpleasant threats both to people and to premises, ... poses quite a threat to our democratic way of life."
The Government, Mr Eggar said, had "considerable concern" about the safety of workers who would have to dispose of Brent Spar. Greenpeace's tactics, he claimed, "amounted to environmental terrorism".
The Industry minister said "difficult legal issues" had arisen as a result of Greenpeace's direct action. "I think it will be necessary for the Government to look at them." He described Greenpeace's victory as "a very serious development. It meant that blackmail succeeded against well-proven scientific evidence."
Greenpeace dismissed Mr Eggar's comments as "idiotic". A spokesman said: "People know our commitment to non-violence is as strong as our commitment to the natural world. We reflect people's views and values, and he obviously didn't."Reuse content