The appeals of four of the trainers disqualified over the Aquanita race day treatments case are expected to be heard together.

Robert Smerdon, Stuart Webb, Tony Vasil and Queensland trainer Liam Birchley are all appealing their bans in the Victorian Civil and Administrative Tribunal.

VCAT on Monday heard the appeals will likely be joined together so they can be heard at the same time.

An unspecified number of witnesses are expected to be summonsed to give evidence at the hearing.

VCAT heard the whereabouts of some witnesses is unknown.

An update on witnesses is expected to be given at the next directions hearing for all four cases on July 25.

Smerdon was disqualified for life and fined $90,000, Webb was banned for four years and Vasil for three years by the Racing Appeals and Disciplinary Board.

Birchley was outed for one year, with Racing Victoria appealing the leniency of the disqualification.

Vasil and Birchley are training on stays of proceedings pending their appeals.

Aquanita stablehands Greg and Denise Nelligan were disqualified for life, trainer Trent Pennuto was banned for two years and stablehand Daniel Garland for one year.