An eight-year-old boy spent 12 hours in hospital after he was bitten by a venomous sea snake off Point Cartwright on Queensland's Sunshine Coast.

James Grisman was swimming in chest-deep waters off Point Cartwright on Saturday afternoon when his mother noticed a black-and-white-banded snake moving in the water near him.

Seconds after Rebecca Grisman yelled out a warning, James started screaming and ran out the water with "blood streaming down his hand" from two visible puncture wounds.

Ms Grisman, who was aware of how deadly a sea snake's venom is, initially tried to find help on the beach.

En route to hospital after a sea snake bite James asked paramedics "am I going to die?". ( Supplied: Rebecca Grisman )

"I didn't have my phone with me as the battery was flat," she said.

"All I could think about was getting to a phone to dial triple-0.

"None of the people who offered help on the beach had a phone on them."

She picked up her son and ran the three blocks to their home where she phoned for an ambulance.

In the seven minutes until paramedics arrived, she followed advice from the triple-0 operator.

"They are so venomous, I was told to put compression on and make him stay still."

When the paramedics arrived, James asked, "Am I going to die?".

"The paramedics were very calm," Ms Grisman said.

"They told him they were 100 per cent sure he wasn't going to die, but James told them that was not possible."

'Warning bite'

The doctors at the Sunshine Coast University Hospital, where James was treated, told Ms Grisman that James was the fourth sea snake bite victim to be treated in Queensland in 30 years.

He spent 12 hours under observation to ensure none of the venom had entered his blood stream.

Ms Grisman said it became clear that the snake had bitten James, but had not injected its venom.

"Apparently the toxins from a snake bite can take several hours before it causes coagulation," she said.

"It obviously bit and let go, a warning bite."

Bite can have 'long-lasting damage'

Sunshine Coast mother Rebecca Grisman said the sea snake which bit her son was similar to this venomous banded sea krait. ( ABC News: Joanna Crothers )

Bites from sea snakes are considered to be rare in Australia.

It is believed that trawler fisherman Harry Evans, who died off the Northern Territory coast in October last year, was the first person to be killed by a sea snake bite in Australia in more than 80 years.

University of Queensland's School of Biological Science's Associate Professor Bryan Fry said most sea snakes found in Australia were highly venomous.

Dr Fry was also only aware of three previous sea snake bites and one was himself while undertaking research in 2002.

He said that bite had "long-lasting damage".

"For two weeks, I couldn't stand and after a month-and-a-half went for a swim and tore my rotator cuffs to the bone because of the muscle damage," Dr Fry said.

"There can be long lasting damage from these bites."

The key is early treatment, including applying a crepe bandage around the wound to stop the lymphatic flow, but not the blood flow.

Snake bite first aid advice: In the absence of arrest, shock or respiratory distress Restrict movement, don't let patient walk

Restrict movement, don't let patient walk Do not wash the bite site

Do not wash the bite site Cover the bite site with a dressing

Cover the bite site with a dressing If bite is on a limb, apply pressure immobilisation bandage, mark the bite site and splint limb

If bite is on a limb, apply pressure immobilisation bandage, mark the bite site and splint limb If bite is on head/torso, completely immobilise patient

If bite is on head/torso, completely immobilise patient Pre-notify hospital if possible Source: Queensland Ambulance Service

"You need to gently compress the flesh and keep it immobile," Dr Fry said.

"It mustn't be too tight though that you cut off circulation."

While brown snakes can cause death in 15 minutes, sea snake venom works more slowly, with Dr Fry describing it as a "case of hours, not minutes".

Despite Dr Fry's traumatic encounter with a sea snake, he said he was still enamoured with the creatures.

"I'm working with animals I love, these things happen, it wasn't the snakes fault," he said.

Dr Fry said most sea snakes were "very gentle animals".

"If you are diving with them, the worst you will see happen is them trying to mate with the regulator hose," he said.

Days after her son's ordeal, Ms Grisman said she was still shocked.

"I've lived locally for 12 years and I've never seen a sea snake before," she said.

"I've always been worried about brown snakes, but I've never seen one of those."