Embattled jockey Danny Nikolic will have to wait until May to face a hearing on assault charges.

A two-day committal hearing due to start in the Melbourne Magistrates Court was adjourned on Wednesday because of a problem with "witness availability".

It was the jockey's second hearing this week.

Nikolic is accused of assaulting another jockey, Mark Pegus, Pegus's girlfriend, Rikki-Lee Hull, and a police officer in three separate incidents last year.

Prosecutor Senior Constable Nathan Sinclair said the case was ready to go but had been delayed until May because of witness availability.

Magistrate Ian McGrane adjourned the case until May 30 but asked Mr Sandy Robertson, for Nikolic, to ensure there would be no further delays.

Nikolic faces a total of six charges including using a telecommunication device to menace a person at Caulfield on January 17 last year.

He was charged with one count of recklessly causing injury, one count of assault and two counts of intentionally causing injury to Mr Pegus at the Caulfield racetrack stables on January 18 last year.

He was also charged with assaulting Ms Hull at the Barkly Hotel on March 7 last year and assaulting police officer Julio Salerno when being questioned at St Kilda police station on April 6.

Nikolic appeared in the Victorian Civil and Administrative Tribunal on Tuesday in a bid to overturn a two-year ban from racing.

After closing arguments that case was adjourned when judge Michael McNamara reserved his decision.

Nikolic had been disqualified over charges that he threatened Racing Victoria chief steward Terry Bailey during a race meeting at Seymour in September.