Hundreds of people attended the funeral of two Canadian brothers who were killed by a python while they slept at a friend's home above an exotic pet store.

Four-year-old Noah Barthe and his six-year-old brother Connor were praised yesterday during the service at St Thomas Aquinas Roman Catholic Church in Campbellton, New Brunswick.

Campbellton Deputy Mayor Ion Comeau said the family decided that the brothers would be buried together in a single casket.

They were found dead on Monday morning after a 100-pound African rock python escaped from its enclosure in the flat where they were staying.

Police say the snake slithered through a ventilation system located above its tank and fell through the ceiling into the living room where the boys slept.

Preliminary post-mortem results show the boys were asphyxiated by the python.

The Rev Maurice Frenette told the boys' parents, Mandy Trecartin and Andrew Barthe, that their lives have been changed forever in ways no one else can imagine.

"We all try to understand the best we can, but you know, no one here can feel what you feel. But I am sure that everyone here feels for you, for what you are going through," he said.

Questions still surround the circumstances of the boys' deaths, but before the service Mr Frenette said the funeral was a time to help the family.

"We're not here today to make any judgment or to try to find an answer to the inquiry, but we are here to take a pause and to be with the family," he said.

"Today we want to basically be there for them and tell them of all the love we will try to share with them during this time of sorrow."

In front of the altar was a photo of the two boys, their heads leaning against each other with broad smiles on their faces. They were remembered for their love of video games, playing outdoors and the differences in their personalities.

Connor was loud and Noah was quiet, but they shared a special bond and "needed to be near each other," said family friend Melissa Ellis.

Provincial officials have said the African rock python was not permitted in New Brunswick.

On Friday, 23 reptiles that were banned without a permit in New Brunswick were seized from the pet store, while four large American alligators were euthanised.

The shop and flat where the boys died are owned by Jean-Claude Savoie, a family friend who took them shopping and to a farm before the sleepover on Sunday with his son.