The practice of "double dipping" - allowing retired military personnel who get a job with the federal government to draw both military retirement pay and a civilian salary - has been outlawed for the future by the House Appropriations Defense Subcommittee.

Chairman George Mahon (D-Tex.) said it was "simply unfair for some people to draw two salaries when other people can't get one."

He said 150,000 retired military personnel currently are employed by the federal government, including 80,000 working for the Defense Department.

The 150,000 draw $1 billion annually in military retirement pay, he said. The total cost of military retirement pay for fiscal 1978 is $9-billion!

Nearly 8 per cent of the 1.1 million civilian employees of the Defense Department are double dippers. The department has 2.1 million military employees.

Though prohibition will apply only to employees newly hired after Oct. 1, 1977, Mahon estimated the limitation would save some $26 million in military retirement pay for fiscal 1978 alone. Under the prohibitation, the employee would have toforego his military pension as long as he was receiving a government salary, but he could pick up the military pension as soon as he left the government job.

For double dippers, the average annual government salary for a retired officer is over $22,000 and for a retired enlisted man over $15,000. The combined salary and pension averages out to $34,000 for an officer and $19,500 for an enlisted man.

In 1964, Congress passed the Dual Compensation Act which said retired officers would have to give up $4,000 annually of their pensions if they took a government job. But that does not apply to enlisted men and reserve officers who make up 95 per cent of the double dippers.

"This is the first effort to make contact with the buzzsaw" of the military retirement issue, Mahon said. He said that as of this moment, if not one more person was ever added to the pension rolls, the government would be liable for an estimated $160 billion in military retirement pay. He said Congress would eventually have to take a hard look at the non-contributory military pensions after 20 years of service, which he said "cost a lot of money."

Defense subcommittee staffer Ralph Preston blamed the military's "up and out" policy for the high number of double dippers in the Defense Deparment.

Under the "up and out" policy any officer not promoted every two years must get out of the military. "The major or colonel who's getting pushed out just arranges to get his old job back wearing a civilian suit," Preston said.

"Many of them would remain in the military if it weren't for the 'up and out' policy."

He said many double-dippers are doing "unnecessary jobs" at the Defense Department, and the hope was that the jobs simply wouldn't be filled if the employee decided to quit rather than give up his retirement pay.

The subcommittee's action came as part of its markup of the $111.2 billion defense appropriations bill. The prohibition will be subject to a vote both in the full committee and on the floor and could be controversial.