Federal travelers who put in more than seven million days on the road each year often complain it costs them money to conduct government business. They claim that Uncle Sam's $35 per diem often forces them to flop into flea-bag motels, or chow down at cheapie hamburger joints in many places. Help is on the way.

Effective Sunday, the government will lift the $35 per diem lid for 70 additional cities and towns. It will bring to 92 the number of areas where the regular per diem limit can be stretched if necessary by federal travelers. Innkeepers and restaurant owners will join their federal guests in the cheering.

The new edict also will move expensive places to visit, like Washington and New York, up to the maximum $50 daily rate - which must be justified - for government employes on official business.

Beginning Sunday, the $35 maximum no longer will apply in 70 newly designated high-cost areas. For example, travelers may spend up to $42 per day in Akron; $47 in Atlanta; $42 in Baton Rouge or, $49 if they must shuffle off to Buffalo (or Niagara Falls) on official business.

Cheyenne, Wyo., will rate $44 maximum under the new travel rules, the same as Dayton. Kalamazoo becomes a $42 town; Kansas City, $48 and the Norfolk area will have a $41 limit. Places that one doesn't think of everyday - Roanoke, Pittsfield, Mass, Eatontown, N.J., and the area around the Picatinny Arsenal, - all rate new per diems above the $35 mark.

The per diem level for Baltimore, Boston and Chicago, Detroit, Hartford, Dallas, Houston, Las Angeles and Las Vegas all move up to $50. So will Washington and New york for visiting feds.

The General Services Administration raised the "actual expense" level for certain cities after complaints from employers about the inadequacy of the standard $35 per diem, and after making its own survey of local living costs in more than 100 area.

For people who come to Washington, New York and other high-cost areas, and find the $50 expense limit too low, help may be on the way. GSA has asked the Office of Management and Budget to raise the actual expense limit for a number of costly areas to $75. OMB is studying the matter.