A father whose 12-year-old son died after inhaling butane gas urged the young people at the funeral yesterday not to experiment with poisons.

"All parents want their children to be safe. I heard children have too many choices in life and should be controlled and behave in a certain way, but at the end of the day I just wanted D to be happy," Jason Lasini said at the service for Darius Logan Claxton, known to many as D.

"D did make a choice, and made a deadly one. To all the young ones here today, air is what you breathe, keeping us young and healthy, not poisons, so make your choices wisely."

Ambulance staff were unable to revive Darius after he tried "huffing" the butane with a group of friends in a carpark in the Christchurch suburb of New Brighton last Friday night.

Online posts have since mocked the death, the Herald has learned.

The posts have now been deleted, but according to one contributor to the RIP Darius Claxton Facebook page, the comments were to the effect that "Darius killed himself and that it was funny that he was dead".

The cause of his death is still to be determined, and police are investigating the sale of the butane to the group.

Yesterday's service, attended by about 200 people in Christchurch, heard that although Darius was given advice, he did what he wanted to do and was his "own man".

Mr Lasini said his son lived his short life "full force".

"The last time I saw Darius was in April ... I was with Jordan, his big brother; it was an unexpected catch-up. I asked Darius was he happy and he said he was. And that meant everything to me."

It is believed the hurtful online comments were made under the name Jimmy Brans, using a fake account.

One person responded: "It's disgusting and the worst thing is he don't [sic] have the guts to evan [sic] use his real name ... if we ever find out who you are, you better pray for mercy."