There was a raft of divisions and miscommunications within the Melbourne Symphony Orchestra about the treatment of pianist Jayson Gillham after he made remarks about Gaza during a recital, new legal documents show.

Gillham’s claim that the MSO discriminated against him because of his political views will reach the Federal Court on Tuesday in what is shaping up as a landmark case about freedom of speech.

Documents filed with the court ahead of the first hearing reveal the MSO was fractured about how to respond when Gillham, a guest pianist, introduced one of his works during a recital in August with a dedication to journalists killed in Gaza and claimed that those deaths appeared targeted.

The next day the MSO wrote to subscribers apologising for the comments, saying they were unauthorised, political, and should never have been made. The MSO took Gillham off the line-up for its Melbourne Town Hall concert scheduled for the Thursday evening, and then cancelled the event.

On the Friday, MSO musicians wrote to the board, conveying concerns about the culture of the organisation, and called for managing director Sophie Galaise and chief operating officer Guy Ross to be sacked.

The musicians also requested an independent review, which has since been announced and will be carried out by former MP Peter Garrett, and an investigation into what happened with Gillham.

The MSO’s managing director at the time, Sophie Galaise, told The Australian on September 2 that the decisions about the concert cancellations were made by the executive team and were unanimous.

Legal documents show Gillham will argue that the MSO contravened the Fair Work Act and caused him “distress, hurt, humiliation and anxiety, as well as damage to his professional reputation”.

The case is against the MSO, Symphony Services Australia, Galaise and Ross personally. All parties were contacted for comment but declined to speak.