The majority of the charges are alleged to have been committed between October 1, 2012, and January 4, 2013, with five indecent assault charges on or about January 3 this year and one of sexual violation alleged to have been committed between December 1 and December 24, 2012.
Rubick was remanded in custody for a post-committal conference on September 18 and will appear again for a second call over on October 2.
Rubick had been working as a DJ for parties but is best known as an athletics coach, notably helping Brad Mathas claim the New Zealand 800m track title in Auckland last year. The pair's working relationship later broke down after nearly seven years.
Detective Senior Sergeant Neil Forlong said in a statement that police believed there might be other young and vulnerable victims and specialist officers were working with Child, Youth and Family to identify and interview these victims.
"I can confirm that police are investigating a number of complaints that date back several years and, as a result, I cannot comment further while the investigation is in progress.
"Extreme care needs to be applied when dealing with sensitive matters such as this and every effort is being made to support the victims and their families," Mr Forlong said.
If anyone has information relevant to the investigation, police encourage them to call Whanganui Police on 06 349 0600.