Tony Blair is gambling with national security with his plans to shake up the armed forces, Michael Howard has said.
The regiment plans have sparked veterans' protests
The Tory leader pointed to plans to cut the number of infantry battalions and claimed there were equipment shortages.
"It's probably only a question of time before the crossed swords of the Army's emblem are replaced by Tony Blair's crossed fingers," he said.
The government says the changes will make the armed forces more able to cope with challenges in an uncertain world.
But Mr Howard said: "At a time of growing threats, instability and new dangers, Mr Blair has decided to cut our armed forces.
"This cannot be right. We cannot afford to gamble with our national security."
He argued the Tories would save the regiments and three frigates to be cut by Labour and spend £2.7bn more on frontline defence.
Their plans would be funded by saving money on defence procurement and other areas of government "waste".
But Defence Secretary Geoff Hoon said the Tory plans lacked credibility because they had not given details of exactly how they would make savings.
"Labour in government has delivered the largest sustained increases in defence spending for 20 years," he said.
"When the Tories were last in office, they cut planned defence spending by 15 per cent during 1994-97.
"Labour is investing the latest battle-winning equipment for our Armed Forces including the biggest shipbuilding order for generations, new fast jets for the RAF and the very latest technology for our soldiers."