A NSW detective heavily involved in the wrongful prosecution of Gordon Wood for the murder of his girlfriend Caroline Byrne today admitted police made a significant error in the investigation.

The revelation came as Wood's lawyer zeroed in on incorrect dates NSW police had applied to important aerial photographs of suicide spot The Gap at Watson's Bay, where Caroline Byrne fell to her death in 1996.

In 2008, following a high-profile trial that has left a legacy of intrigue, Wood was found guilty of throwing his model girlfriend off a cliff - a claim he always denied.

After he served three years of his sentence, Wood's conviction was proved wrongful and was overturned in 2012.

Now 54, Wood, once a driver for high-profile stockbroker Rene Rivkin, is suing the state of NSW for almost $20 million for malicious prosecution.

Today, NSW detective sergeant Paul Quigg, who worked on the investigation, admitted there had been discrepancies in the body of evidence built by police.

Gordon Wood (left) and his former girlfriend Caroline Byrne (right)

Under questioning by Wood's lawyer, Detective Sergeant Quigg was presented an email sent to him by the NSW crown prosecutor's office.

It requested aerial photographs of the ledge taken around the time Ms Wood had died, so that vegetation and terrain could be considered.

"Did you ever reply?" Bruce McClintock, SC, asked.

"I can't recall," said Detective Sergeant Quigg.

Mr McClintock, SC put it to Detective Sergeant Quigg that the condition of the cliff in June 1995 was "a critical matter" and that it had been "a significant failure" in the investigation. Detective Sergeant Quigg agreed that it had been a mistake.

The vegetation on the cliff face was important to the prosecution because it had allowed University of Sydney Associate Professor Rod Cross to reinforce his theory about how Mr Wood could have thrown his girlfriend from The Gap.

Caroline Byrne in a modelling photo released by Sydney etiquette teacher June Dally-Watkins

Associate Professor Cross, an expert in physics, had worked with NSW police to show how a man with a precise and clear run up could have spear thrown a limp body to the location where Ms Wood was found on the rocks below.

It was pointed out to Detective Sergeant Quigg by Woods' lawyer that NSW police had appeared unwilling to find and use photographs of The Gap taken around 1996.

Mr McClintock, SC also repeatedly asked Detective Sergeant Quigg why Prof. Cross had appeared to be so heavily involved in the police investigation, being invited to meetings and privy to NSW police emails.

One key aerial photograph Prof. Cross used in his controversial report to help prove his hypothesis had been dated incorrectly, stating it had been taken in 1996 instead of 2003.

Prof. Cross has since claimed that it was Detective Sergeant Quigg who advised him the date of the photo was 1996. Detective Sergeant Quigg told the court today that he rejected that statement "100 percent".

Detective Sergeant Quigg also told the court how, for several months after the investigation began, he had been unaware that photographs of the crime scene did not accurately portray where Ms Woods body had fallen.

Explaining his concern over the discrepancy, Detective Sergeant Quigg said "it was very important to determine actual location of where Caroline Byrne's body was located and recovered."

To succeed in his lawsuit, Wood's legal team must prove the prosecution against him was maintained without NSW police officer reasonable and probable cause.

The hearing continues, with Detective Inspector Paul Jacobs, the man who led the investigation into Caroline Woods' death, giving evidence this afternoon.

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