She debuted with the Croatian national team in 1995, at the junior European Championship in Ankara. In 1997 she was declared best player at the Junior European Championship in Slovakia, where Croatia won the silver. In 1998 she played at the junior European Championship in Belgium as well as the senior World Championship in Japan. With the senior national team she played at the 1999 World Cup in Sweden. In the same year, Siscovich played in Brema in the tournament of qualification to the Olympic games, finishing third with Croatia. Siscovich won the silver medal at the European Championship in Rome in 1999. She also represented Croatia at the 1999 Military Games in Zagreb, winning the gold medal.