A lawyer for Daniel Morcombe’s parents says they know there is not much they can do about their son’s killer appealing against his life sentence.

Daniel Morcombe’s parents expected their son’s killer to appeal against his conviction, their lawyer says.

Brett Peter Cowan, 44, is taking his case to the Queensland Court of Appeal arguing the jury should never have heard his confession to undercover police.

Cowan is also appealing on other aspects, including prejudicial media coverage and the fact the trial judge did not allow several defence witnesses to give evidence.

Bruce and Denise Morcombe’s lawyer Peter Boyce said they were not surprised by the appeal.

“Obviously they’d like to see the end of what they’ve been through, but they recognise that’s part of the process and there’s not much we can do about it,” Mr Boyce told ABC radio.

“I’d be surprised if it’s not finished by the end of the year.

“I would think it would be over and done with by then.”

The Morcombe’s son Daniel, 13, was abducted in 2003 on Queensland’s Sunshine Coast while waiting for a bus to go shopping for Christmas presents.

Cowan was convicted of his murder, in part because of a recorded confession he made to undercover police masquerading as gangsters before leading them to Daniel’s burial site.

The father of three was last month found guilty of murder and indecent treatment of a child and sentenced to life in jail with a non-parole period of 20 years.