Ivanovic's contract with Kontic ran through Wimbledon and following "amicable discussions, the pair decided not to renew it," said the website.
The move comes as Ivanovic is having some of her best results since winning the 2008 French Open. She has won three WTA titles this year and reached the quarterfinals of the Australian Open, defeating world No. 1 Serena Williams.
The Serb had repeatedly said a large portion of her success was because she was more comfortable having a team from the same country as her and that gave her strong backing.
She is expected to name a new coach during the hard court season.