David Cameron's government has been accused of dragging its feet over aid for the North Sea after reports another 100 jobs in the sector are at risk.

The concern followed an announcement by energy giant Schlumberger that it is cutting 9,000 posts worldwide.

The firm, the world's largest oil and gas services group, blamed the "dramatic" fall in the oil price in the last three months.

The latest blow came as oil expert Sir Ian Wood, who led a review into the future of the industry for the Coalition, called on ministers to cut corporation tax rates in the next three weeks to help stave off further job losses.

But Treasury ministers and Downing Street both suggested that any help would be announced in the Budget in March.

Chief Secretary to the Treasury Danny Alexander said ministers would take the time to get the right policies in place.

He said: "I think that it is right to say, with the Budget just a few weeks away, let's use that time to make sure we have the right, comprehensive measures to support this crucial industry,."

That view was echoed by Downing Street.

Asked if the Chancellor might look at help sooner than March's Budget No 10 pointed to tax cuts that came in in at the start of this month, adding:: "In terms of further decisions those are matters that are considered at fiscal events - and obviously the Chancellor has set out the date of the Budget".

Mark McDonald, the SNP MSP, accused Coalition ministers of moving "like lightning when it comes to increasing taxes on the oil & gas industry, but like treacle when the sector needs assistance. People's jobs are on the line and Westminster needs to act now to give the oil & gas sector the support it needs."

The row came as employers and unions met to discuss how to mitigate the effects of the slump in oil prices, which fell below $50 a barrel earlier this week.

Unions fear more bad news is on the horizon, after BP announced this week that 200 jobs and 100 contractor roles would scrapped following a review of its North Sea operations.

Earlier Sir Ian called on ministers to cut the corporation tax that North Sea oil companies pay.

He said: "The key, frankly, is to stabilise the industry, avoid a real crisis of confidence and ensure they can see a sustainable future. There's nothing that can be done short term... there are a good range of fiscal changes on the table... they came from the November budget, particularly important on the fuel allowances. There are a number of good things in the industry. .. the industry is embarking on a major cost reduction exercise. There's virtually nothing, fiscally, that can be done at ($45 a barrel) to have any impact because at that stage, very few operators are making profits, and not paying taxes.

"What is really important is to look now, and set a tax regime that makes it absolutely clear, it's a medium-term tax regime... as the oil price recovers. It's got to, in my opinion, include at least a 10% tax reduction... to take it down to 50% for normal corporation tax. On that basis, hopefully operators will have the motivation... through what's going to be a very difficult period."

Ms Sturgeon has written to the Prime Minister asking for "substantial package of measures be announced without further delay to safeguard investment, jobs and the long-term sustainability of the North Sea."

SNP Energy minister Fergus Ewing also called on the UK government to act before the Budget in March.

"It is clear to me that the UK government has accepted it must act on tax," he said, "My question is why wait until March?"

A spokesman for Schlumberger said: "The dramatic fall in oil price over the past quarter has led our customers to decrease exploration and production activity worldwide. As a result, Schlumberger is reducing headcount in line with lower activity levels."

She refused to comment on reports around 100 North Sea jobs were at risk.

Mick Cash, general secretary of the Rail, Maritime and Transport union, said the move was "yet more bad news at the end of what has been a grim week for the offshore industry."

He warned that all the signals were the situation would get worse, as he accused companies of a "slash and burn cuts" policy and accused politicians of a lack of decisive action.

Oonagh Werngren, from industry body Oil & Gas UK, said it was working hard with the Coalition Government on fiscal and regulatory reforms to help safeguard the long term future of the industry.