An inquiry into Kathleen Folbigg’s convictions for killing her four babies has reinforced her guilt, a former NSW District Court chief judge has found.

Reginald Blanch QC, who presided over the inquiry, has concluded he does not have “any reasonable doubt as to the guilt of Kathleen Megan Folbigg”, in a report made public on Monday night.

The 51-year-old mother was jailed in 2003 for at least 25 years for killing her four babies – Caleb, Patrick, Sarah and Laura – in the decade from 1989.

The report finds “no error or procedural irregularity in the trial process” and the “trial has not resulted in a miscarriage of justice or irregularity that gives rise to a reasonable doubt as to Ms Folbigg’s guilt”.

The inquiry took place after Folbigg’s lawyers lodged a petition in 2015 casting doubt on some of the evidence that led to her conviction.

Kathleen Folbigg was jailed in 2003 for at least 25 years of killing her four children. Photo: justiceforkathleenfolbigg.com/Twitter

“It remains that the only conclusion reasonably open is that somebody intentionally caused harm to the children, and smothering was the obvious method,” Mr Blanch’s report said.

“The evidence pointed to no person other than Ms Folbigg.”

NSW Attorney-General Mark Speakman announced an inquiry in 2018 after Folbigg’s lawyers lodged a petition casting doubt on some evidence that led to her conviction.

At the time, Mr Speakman said he’d formed the view it was necessary “to ensure public confidence in the administration of justice”.

He has spoken with Craig Folbigg, Folbigg’s ex-husband and the babies’ father, regarding the report.

“I acknowledge that the decision to commence an inquiry has further aggravated what already was an unimaginable tragedy,” he said in a statement on Monday.

“I am sorry for the toll that the inquiry has taken on Mr Folbigg and family members over the last year.”

Mr Speakman said he hoped the findings “might provide comfort in some way to the relatives of Caleb, Patrick, Sarah and Laura, and will dispel community concern regarding Ms Folbigg’s convictions”.

Craig Folbigg’s brother, John, in May 2019 described the inquiry as “most unnecessary and most definitely unwelcome”.

“However we have endured it as ultimately it would, we feel, help to ensure that the justice that Caleb, Patrick, Sarah and Laura received in 2003 is upheld, ” he said.

Folbigg will continue to serve her 30-year sentence, and will be eligible for parole in 2028.

-AAP