The cases relate to the separate searches of ACC claimants Bruce Van Essen's and Jason Patterson's homes in 2006, which both say were "unlawful and unreasonable".
Both search warrants were as a result of investigations by Dunedin private investigators who were engaged by ACC to investigate possible fraud. The private investigator in Mr Van Essen's case was Peter Gibbons, while in Mr Patterson's case it was Graham Scott.
Justice Christian Whata ruled in the High Court at Dunedin yesterday that the cases should be heard together.
Mr Van Essen told the court the search of his home in September 2006 had affected his mental health and the relationship with his partner and family.
Mr Van Essen, who broke down at times while giving evidence, said since the search he was in constant fear of being put through the same ordeal again.
"I feel horribly insecure not only in my home, but also in public," he said.
The failure of police to return a memory stick containing "intimate" images of him and his partner obtained during the search also worried him.
"I am mortified that it might end up in the wrong hands."
He also complained that police failed to show him a search warrant and did not observe non-police officers, private investigator Mr Gibbons, non-sworn Dunedin police employee Kelly Knight and an ACC employee, who took part in the search.
He said there was no need for the search to take place as he would have provided the information to ACC anyway.
"I have never attempted to nor defrauded them in any way."
Counsel for the Attorney-general Fergus Sinclair said under cross-examination the police officers involved in the search, Constable Andrew Henderson and Sergeant Sheldon Kindley, remembered presenting a search warrant and observing the non-police officers throughout.
They also did not believe they had taken the memory stick from the property, Mr Sinclair said.
He put it to Mr Van Essen that given his "distressed" emotional state at the time of the search his memory could be incomplete.
Mr Van Essen replied saying that while he was distressed at the time, his memory was clear.
Counsel for Mr Gibbons David Robinson, who is also representing Mr Scott, referred to Mr Van Essen's Trademe account and work as a computer technician, saying it was reasonable to come to the conclusion that Mr Van Essen was involved in commercial activity while receiving ACC payments.
Mr Van Essen and Mr Patterson both say that police were in breach of the Bill of Rights Act 1990 when they searched their homes and that both police and private investigators were trespassing in carrying out the search.
They also say police acted in an improper manner and with malice against them.
Mr Van Essen also says Const Henderson acted with malice when procuring a search warrant against him.
Const Henderson is the son-in-law of the private investigator, former senior Dunedin detective Mr Gibbons, whom Mr
Van Essen is also suing.
In his opening statement, counsel for Mr Van Essen, Michael Starling, who is also representing Mr Patterson, said the search warrant was obtained on the basis of information provided to police by Mr Gibbons which contained "numerous errors and or misleading statements".
In swearing an affidavit for the search warrant, Const Henderson failed to acknowledge that Mr Gibbons was his father-in-law and failed to independently verify the allegations made against Mr Van Essen.
Justice Whata earlier ruled out an application for both cases to be stricken out saying it was "preferable" for issues to be raised in a "full trial".
The case continues.