''Grave'' gaps in equipment in the West German armed forces mean that NATO could hold off the first echelon of any Warsaw Pact attack for only seven days, according to Der Spiegel.
In its Aug. 13 issue the news magazine says that Inspector General Wolfgang Altenburg documents, in a still-secret report written last January, crucial shortages in ammunition and major gaps in reconnaissance, communications, and electronic warfare and counterelectronic equipment.
This would not hold the front line for the 10 days needed to bring in American reinforcements, General Altenburg concludes, according to Der Speigel. NATO would therefore have to resort to nuclear weapons early on in any war.
This criticism is one that NATO Commander Bernard Rogers has often voiced publicly, though he has carefully not specified the exact number of days he would expect NATO to hold out conventionally before having to go nuclear.
So far the Bonn Ministry of Defense, which has an uphill fight in extracting money from the Finance Ministry for procurements in the areas mentioned by Der Spiegel, seems less than upset by the magazine's revelations. While calling Der Spiegel's article a mix of ''half-truths, speculation, and old news,'' Defense Ministry Secretary of State Peter Wurzbach didn't deny the substance of Der Spiegel's description of armed forces deficiencies.
Instead, in an interview with the dailies Die Welt and the Frankfurter Rundschau Monday, Mr. Wurzbach blamed the previous center-left government and said the present two-year-old center-right government was carrying out corrections. Altenburg and staff of the Defense Ministry have been working out a comprehensive 15-year plan for improvements, Wurzbach said, that will go to the Cabinet and Parliament for approval this fall.
Included in this plan will be consideration of how the cuts in the present 495,000-strong armed forces might be kept to a minimum when the number of draft-age men drops sharply beginning in 1987. Der Spiegel writes that, even with laxer qualification standards and an increase in the term of conscription from 15 to 18 months, Altenburg calculates total strength must drop to between 420,000 and 450,000.
Der Spiegel listed Altenburg's top priority in the 15-year plan as building up ammunition stocks and acquiring modernized communications and reconnaissance equipment. His second priority is outfitting present airplanes with more capable bombs and missiles for attacking Warsaw Pact airfields. And his third priority is said to be procurement of weapons (including cruise and other conventional missiles) for hitting second-echelon targets such as railroad junctions and depots well behind the adversary's front line.