The phrase "undue interference" means unnecessary or excessive involvement or intervention in a situation. It refers to when someone or something interferes more than is reasonable or justified. Full definition
The free market has to do with freedom of marketing commodities without undue interference from outside powers that may seek to control it. (religion-online.org)
The judiciary should be encouraged to have the courage to exercise its powers without undue interference by the executive arm. (newsdiaryonline.com)
Academic researchers are supposed to contribute to the public good, and scholars are supposed to have academic freedom to explore important questions without undue interference. (scientificamerican.com)