Greenpeace activists in a tiny inflatable boat on Monday intercepted a Russian ship in the remote Arctic as it was taking oil workers for the pioneering start of drilling work in pristine northern waters.

The second raid against Gazprom operations in three days comes as Russia takes the lead from other Arctic powers in exploiting what is thought to be one of the world's largest untouched deposits of oil and natural gas.

Six Greenpeace International activists occupied Gazprom's rig in the southeastern section of the Barents Sea on Friday for 15 hours before leaving after being pelted by workers with chunks of metal and hosed with ice water.

Greenpeace said its Executive Director Kumi Naidoo -- a South African who led Friday's action -- and six others raced toward the same platform at dawn Monday to intercept a passenger vessel carrying a Gazprom replacement crew.

Pictures of the sea saga showed the six then chaining their black rubber boat to a huge Russian ship that had anchored just a few hundred metres (yards) away from the Gazprom rig.

One photo showed the Russian ship's crew hosing the activists with a powerful stream of water in the frigid weather.

"The force of the water was so intense it knocked my boots off!" Greenpeace quoted one activist aboard the boat as saying.

"Felt like we were in a hurricane," the unnamed activist said. "All you can taste is salt."

Greenpeace Russia member Yevgenia Belyakova said the threat of frostbite after the water dousing had forced the crew to disengage from the anchor after seven hours and take cover in an accompanying Greenpeace speedboat.

But the team said it was still managing to keep Gazprom workers from assuming their place on board the oil platform by circling the Russian ship.

Gazprom refused to comment and addressed all questions to SevMash -- a huge state firm that makes nuclear submarines and both built the floating rig for Russia's largest energy company and chartered the new crew's ship.

A spokeswoman said SevMash was "in full control of the situation" but refused to make any further comment.

Gazprom is due next year to begin producing up to seven million tonnes of oil annually from the country's first field in the fragile Arctic.

The unit plans to drill and process oil before pumping it into tankers -- operations that have never been performed in such an inhospitable climate -- and is being watched closely by other energy giants planning to pursue similar work.

But critics warn that such operations are extremely risky because the base is sealed in ice for most of the year and has to work smoothly in temperatures that often plunge to minus 50 degrees Celsius (minus 58 Fahrenheit).

Naidoo tweeted several hours into the raid that the global green action network was "finishing what we started" on Friday in a bid to raise global awareness of the impending Arctic operations.

Gazprom is set to be joined in the Arctic soon by the US super-major ExxonMobil and Russia's state oil holding Rosneft -- an alliance sealed last year as part of Kremlin efforts to finally tap an area it views as the future of Russia's energy wealth.

Russia is one of the world's top two oil producers and the world's top exporter of natural gas.

But its crude production has been stalling and is soon set to decline as old Soviet era wells developed in Siberia start to slowly run dry.