FURTHER exploration and investment in the North Sea now depends on "substantial tax reductions" for operators, Nicola Sturgeon has warned.

Speaking ahead of tomorrow's crisis summit in Aberdeen between the oil industry and Scottish and UK governments, the First Minister stepped up calls for the Treasury to ease the tax burden on producers hit by the collapse in oil prices.

Chancellor George Osborne has hinted at more help, but not before his budget on March 18.

But with job losses, pay cuts and wages freezes already being announced, Sturgeon said dramatic fiscal and regulatory change was needed now.

"In the short term, that means urgent action on taxation to give the industry the certainty and security it needs to protect jobs and investment.

"It is essential the tax reductions are sufficient to instil investor confidence, as without that maximised recovery will not be achieved."

LibDem Scottish Secretary Alistair Carmichael said: "The UK Government has used its size and strength to stand squarely behind this vital industry and will continue to do so.

"The broad shoulders of the UK economy means it can invest in the industry and support it even when the price of oil suffers significant falls."