"There are big geological structures on the Norwegian shelf that could also handle carbon dioxide from other nations in the North Sea basin -- Denmark, the Netherlands, Britain -- the closest countries with big carbon dioxide sources," he said.

Norway is the world's number three oil exporter behind Saudi Arabia and Russia and western Europe's biggest gas exporter. The UN's Kyoto Protocol sets caps on carbon dioxide emissions by 35 industrial nations as part of a drive to brake warming.

Enoksen said the oil and energy ministry was studying legal hurdles to storing carbon dioxide -- some linked to the London Convention on marine pollution -- but expressed confidence that they could be overcome.

"I think it will be fine," he said during a conference on carbon dioxide in Trondheim, mid-Norway.

He said that carbon dioxide was viewed as industrial waste when stripped, for instance, from the exhaust of a power plant or a cement factory -- even though CO2 is not toxic.

"It's a problem when it (carbon dioxide) is waste. When you clean up energy it becomes waste," he said. "We are trying to clarify this legally, cooperating with British authorities."

QUICK FIX

Norway agreed with Britain last year to examine the potential of CO2 storage, a possible quick-fix to global warming in a world reliant on coal, gas and oil.

Many scientists say that a buildup of carbon dioxide in the atmosphere, mainly released by burning fossil fuels, could trigger disastrous climate changes such as more powerful storms, droughts, heatwaves and rising sea levels.

Norway's Statoil has been reinjecting a million tonnes of carbon dioxide a year at its Sleipner gas field since 1996, one of three such projects in the world alongside schemes in Canada and Algeria.

Sleipner does not qualify as dumping because the carbon dioxide comes from processing natural gas at the platform and so is exempt from dumping regulations, Enoksen said.

High costs could be a far bigger hurdle than legalities.

A study by Norwegian pipeline operator Gassco of the storage potential at six oil and gas fields off Norway said such projects would all run at big losses even if the CO2 were used to boost oil recovery.

And the International Energy Agency reckons that typical costs of stripping out carbon dioxide, transport and storage could be US$35-$55 a tonne.

Enoksen said new technologies, mechanisms to spur higher market prices for carbon dioxide or new government incentives could make storage more attractive in the long term.

Enoksen also said Norway would reach its goals under the Kyoto Protocol of limiting any rise in emissions to one percent above 1990 levels during 2008-12.