Activists face prison time after Woodside gas rig stunt

The pair spent the night on the 70,000-tonne floating platform after gaining access at around 5:45am on Saturday, protesting what they say are environmental threats to the nearby Scott Reef.

They were arrested and removed from the platform by authorities before being transported to the mainland.

They have since been charged with interfering with offshore petroleum installations or operations, which carries a maximum penalty of 10 years' imprisonment.

They are due to appear before the Karratha Magistrates Court on Monday.

Investigations into the circumstances surrounding the incident are continuing, Australian Border Force said.

"Offshore petroleum facilities operate in inherently complex and potentially hazardous environments," ABF said in a statement.

"Unauthorised access is unlawful and can place both trespassers and workers at significant risk."

Greenpeace confirmed that two of their activists had been arrested in a statement to AAP, adding that the pair are "safe and in good spirits."

"Greenpeace Australia Pacific always takes responsibility for our actions and stands behind our activists through the course of this process. This was a safe and peaceful protest against Woodside to save Scott Reef and our activists were highly trained and experienced," the group told AAP.

Woodside condemned the stunt, denying that it was peaceful and that it endangered not only the activists themselves but Woodside staff, contractors and law enforcement responders.

"The activists' conduct is not peaceful. It is dangerous, reckless and illegal," a spokesperson for the company said.

The Scarborough Energy Project is 98 per cent complete and set to produce its first liquid natural gas by the end of 2026. The initial stage includes eight wells with 13 to be drilled over the life of the field.

The massive floating production unit arrived at the site in mid-January after being slowly towed from China.