Chancellor Helmut Kohl has decided to dismiss West Germany's intelligence director and to replace him with Hans-Georg Wieck, Bonn's ambassador to the North Atlantic Treaty Organization for the past five years, sources close to Kohl said.

The change will be announced formally Thursday, they added.

The chancellor acted after receiving the final report today on the defection to East Germany last week of top spy hunter Hans Joachim Tiedge. The outgoing intelligence director, Heribert Hellenbroich, was forced into early retirement because he failed to remove Tiedge as a security risk even though he knew for some time about the counterspy's severe drinking and debt troubles.

Meanwhile, Bonn's broadest espionage scandal spread beyond West Germany's borders when Britain and Switzerland announced the arrest of two couples suspected of spying for East Germany.

Security officials said West German counterintelligence had informed the two governments and urged them to arrest the suspects before they managed to reach sanctuary in East Germany.

The arrests appeared to be the first actions taken by other western governments against Soviet Bloc spies because of information obtained during the current spy investigations in West Germany.

Security sources said the couple seized last Sunday in Luzern by Swiss police were believed to be control agents for Margarethe Hoeke, a secretary in the office of West German President Richard von Weizsaecker. She was arrested last Saturday on spy charges.

Hoeke worked for the president's assistant for foreign and security affairs and reportedly had access for nearly 20 years to highly classified material, including all of the country's incoming diplomatic cables and reports on confidential talks with visiting leaders.

In London, an East German couple, Reinhard and Sonja Schulze, were taken into custody after being charged with passing information to a possible enemy. Security officials said the arrests in Britain were linked with Tiedge's defection. Under Britain's Official Secrets Act, a conviction could bring a prison sentence of up to 14 years.