Defence Secretary Liam Fox says avoiding civilian casualties is driving up costs for the military campaign in Libya ahead of an expected announcement that the bill has hit £250 million.
However, Dr Fox insisted the spending is worth it because it shows Britain holds the "higher moral ground".
Treasury Chief Secretary Danny Alexander sparked speculation about the price of operations at the weekend when he suggested it was running into "hundreds of millions".
The figure was far higher than the tens of millions predicted by Chancellor George Osborne when the campaign against Muammar Gaddafi's forces began in March. Some experts are suggesting the cost could rise to £1 billion if raids drag on into the autumn. The spending is being met from Government reserves rather than normal budgets.
Speaking ahead of his written statement to the House of Commons, Dr Fox said people will "have to take into account that we have used more expensive precision weaponry so that we minimise civilian casualties in Libya".
"And if we are going to fight operations in the future based on minimising civilian casualties there is clearly a financial price to pay," he said. "But I think that that shows that we are on the moral high ground and that we place a higher value on human life than the Gaddafi regime does."
Prime Minister David Cameron has insisted that British forces can maintain the current level of operations in Libya despite concerns raised by senior military figures. He told MPs the Strategic Defence and Security Review (SDSR) had allowed for flexibility in the armed forces.
Air Chief Marshal Sir Simon Bryant, the RAF's second in command, has said operations in Afghanistan and Libya are together placing a "huge" demand on resources.
Last week, head of the Royal Navy Admiral Sir Mark Stanhope questioned the sustainability of current military operations, saying the Government would have to make "challenging decisions" if the Libya mission lasted more than six months. This prompted Mr Cameron to warn top brass: "You do the fighting and I'll do the talking."
Meanwhile, cracks in the Nato-led coalition appeared to surface on Wednesday, with Italy calling for a ceasefire.
