Commonwealth Games organisers are under fire for the delay in getting help to a stricken Scottish athlete who collapsed with heatstroke while leading the men's marathon with just 2 kilometres to go.

Callum Hawkins had looked set for a comfortable victory in the men's marathon before succumbing to the Gold Coast heat. Temperatures reached 28 degrees by the late stages of the race.

The sight of Hawkins crashing into the bridge railing and collapsing on the road sparked an angry reaction from commentators and on social media, with Games organisers and nearby spectators criticised for their reaction.

BBC Sport commentator Steve Cram said it was disgraceful that paramedics took so long to attend to Hawkins.

Medical staff cool down Callum Hawkins after his collapse in the Gold Coast heat. ( AAP: Tracey Nearmy )

"I'm just concerned for his welfare. He hit his head on the barrier. I'm sorry if you're watching this at home, it's really distressing. He's going to hurt himself and there's nobody anywhere near," he said.

"We should have some more medical attention. This is a guy in real distress and someone needs to recognise it for his health at this point.

"Where on Earth is the help? You cannot just wait at the finish line. They've got radios. And finally somebody arrives. I think it's disgraceful."

British marathon champion Paula Radcliffe added to the criticism, questioning Commonwealth Games organisers and medical support staff's handling of Hawkins's condition.

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"Congratulations to all the runners who finished and brave running from Robbie Simpson and Kevin Seaward but big questions for LOC [local organising committee] and medical support. That should never happen," she said on Twitter.

"Medics were shockingly slow to get there and then to act when they did. The athlete will always want to finish but isn't able to think rationally at that point."

In defence of the paramedics, GOLDOC chief executive Mark Peters said it was not possible for medics to be positioned on "every kilometre" of the track.

But he did say officials would review whether the response time was reasonable.

A paramedic treats Callum Hawkins after his collapse during the marathon. ( AAP: Tracey Nearmy )

"We need to check the facts out … obviously the health of the athlete is absolute prime," he said.

Mr Peters said there was "no reason" there would be deliberate delays.

"Sometimes medical people arrive and the athlete has to make a decision as to whether they want to go on or not. I understand that was part of a discussion at a point in time, because incredibly athletes in whatever state they are want to finish," he said.

Mr Peters said he was worried about the actions of some spectators when Hawkins collapsed.

"I was also concerned about the behaviour of a small number of bystanders who chose to take images. This is not in keeping with the spirit of GC2018," he said.

Michael Shelley of Australia (right) passes Callum Hawkins of Scotland after he collapsed. ( AAP: Tracey Nearmy )

Radcliffe did defend race winner Shelley against social media criticism claiming he heartlessly ran past Hawkins on his way to claiming gold in the event.

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"That isn't fair. He hasn't seen what we saw and was hanging on by a thread at that point as well. Fault is with organisers, medics and some spectators not with the other athletes," she said.

Team Scotland wrote on social media that Hawkins had been taken to hospital for monitoring, but medical staff had "no major concerns" about his condition.

In a later tweet, Team Scotland wrote that Hawkins was sitting up and talking, but was undergoing further tests as a precaution.