The US Open champion hired the German, best known for guiding Angelique Kerber through her professional career, at the end of last season but it has proved another short-lived relationship.
Raducanu said in a statement: "I want to thank Torben for his coaching, professionalism and dedication over last half a year. He has a huge heart and I have enjoyed our strong chemistry during the time together.
"I feel the best direction for my development is to transition to a new training model with the LTA supporting in the interim."
Beltz had previously guided Kerber to Australian and US Open Grand Slam titles in 2016. His replacement will now be Raducanu's fourth coach in a year.
Nigel Sears worked with the British number one but got replaced by Andrew Richardson after last season's Wimbledon.
Despite helping guide Raducanu to glory at the US Open in New York, his contract was not renewed.
Raducanu has recently spent time preparing for the clay court season at Riccardo Piatti's academy in Liguria.
The Italian coach has previously worked with Richard Gasquet and Ivan Ljubicic and recently split from Jannik Sinner after working with him throughout his teenage years and helping him break into the top 10.
Raducanu reached the quarter-final's in last week's Stuttgart Open and has won three of five games on clay so far, including a win for Great Britain at the Billie Jean King Cup qualifier in Prague.
The 19-year-old, who continues her clay-court baptism in Madrid this week, will lean on the Lawn Tennis Association in the short term.