Police have charged a Sunshine Coast groom with murder after allegedly stabbing his brother to death following a "very violent argument".

Police said the dead man, Gregory Kenneth Robbins, had flown from interstate to attend his brother's wedding which was planned for this weekend.

Mr Robbins, 61, from Perth, was stabbed several times in the torso at a home on Hamilton Street in Buderim on Wednesday night.

A police officer scours the Buderim home where Mr Robbins was stabbed. ( ABC News: Bruce Atkinson )

He was rushed to hospital with critical injuries but died hours later.

Former Australian Army rifleman Matthew Mitchell, who lives next door, said he jumped the fence to provide first aid to Mr Robbins until ambulance crews arrived.

"I heard a bit of a screaming match that escalated then stopped ... then it was followed by some ladies screams," Mr Mitchell said.

"I asked what was going on, I didn't get a response and heard a lady saying, 'don't let him die' — when I heard that I jumped the fence."

Mr Mitchell said he found Mr Robbins leaning against the inside of the garage, curled over, surrounded by family members.

"After a little bit of hesitation, they told me he'd been stabbed.

"When I realised the situation I went into first-aid mode and patched him up as good as I could [then] jumped on the phone to emergency services," he said.

Neighbour and former soldier Matthew Mitchell jumped the fence to help. ( ABC News: Bruce Atkinson )

Mr Mitchell said he had extensive first aid training with the Army and all that was going through his head was "fix him and get him to the hospital".

"You don't really think about it, you just do it," he said.

"I've only been out of the Army three months, so it's still fresh."

'A minor family dispute escalated'

Detective Sergeant Chris Eaton said police have charged Mr Robbins' 57-year-old brother, Bernard John Robbins, from Buderim, with murder.

"Police will allege that the male victim has travelled from Western Australia in the past couple of days to actually attend the wedding of his brother," he said.

"We will allege that there was a relatively minor family dispute which escalated into a very violent argument."

The men were not known to police and detectives are investigating whether alcohol was a factor.

Detective Sergeant Chris Eaton said the family were heartbroken. ( ABC News: Bruce Atkinson )

Another neighbour, Benjamin Fox, said he believed the brothers were having a few drinks earlier on, and he also heard yelling.

"I think it's hard on everyone around here, the neighbours and stuff. It's a little bit scary, kids were a bit worried this morning and then my other half," he said.

Detective Sergeant Eaton said two other people were at the house during the alleged attack.

"For someone to have a family member who dies under these circumstances is absolutely tragic," he said.

"But of course, for someone's relative to be arrested and charged with that offence, you can only imagine the heartache that compounds for the family and friends.

"The dangers of a knife are self-evident ... on this occasion it would appear it has resulted in the most tragic of endings."

The matter was heard in Maroochydore Magistrates Court today and adjourned to August 9.

The incident is the second fatal stabbing in south east Queensland in as many days.

Detectives on Wednesday charged a woman with murdering her boyfriend at a home in Annerley, on Brisbane's south.