Police have compiled about 3000 pages of evidence for claims that the Catholic Church covered up allegations of child sex abuse by two NSW Hunter Valley priests, an inquiry has been told.

But a decision on whether charges should be laid against senior priests or church officials is not expected until later this year at the earliest.

The evidence was gathered in a police investigation codenamed Strike Force Lantle, set up in late 2010 to look at complaints made by four alleged victims about Father Denis McAlinden and Father James Fletcher between 1985 and 1999.

Ian Lloyd QC was engaged by government officials earlier this year to review the Lantle investigation for the special commission of inquiry that began in Newcastle 10 days ago.

The inquiry, sparked by police whistleblower Detective Peter Fox, is looking at the way police and the church have handled child sex allegations, particularly those involving McAlinden and Fletcher, who are both dead.

The first stage of the commission is scheduled to end on Monday, and the second stage is scheduled from June 24 to July 12.

Commissioner Margaret Cunneen is due to report by September 30.

Mr Lloyd told Ms Cunneen the strike force Lantle evidence was world class.

"In all my years in prosecuting crime, which are approaching 37, it was as thorough as I have ever seen," Mr Lloyd said on Friday.

Told that it took five months from when the strike force was set up to the start of investigations, Mr Lloyd said, "Given the historical nature and complexity of the investigation, I don't see that as surprising or unreasonable."

He said it was "entirely appropriate" to limit the strike force's terms of reference to the alleged actions of two priests and the evidence of four witnesses, "otherwise it could go on forever".