An outstanding act of sportsmanship between two track and field athletes, described as illustrating the "Olympic spirit", has brought the crowd to its feet at the main stadium in Rio.

New Zealand's Nikki Hamblin and Abbey D'Agostino of the US both advanced to the women's 5,000 metres final, but in dramatic and emotional circumstances, after they were involved in a fall late in the second heat on Tuesday (Rio time) when both athletes crashed to the track.

In an act which conjured up memories of John Landy helping the fallen Ron Clarke back on his feet at Melbourne's Olympic Park in 1956, D'Agostino assisted Hamblin up off the track but the American was injured as a result of the fall.

Hamblin gave up any chance of chasing the main pack, which included Australians Eloise Wellings and Genevieve LaCaze, and instead waited until the hobbling D'Agostino could continue the race, as the sparse crowd at the Olympic Stadium rose to their feet and applauded.

Hamblin stops running during the race to help a limping D'Agostino. ( Reuters: Kai Pfaffenbach )

Both finished, Hamblin in 15th place in a time of 16:43.61 and a struggling D'Agostino 16th in 17:10.02, well behind heat winner Almaz Ayana of Ethiopia, who stopped the clock in 15:04.35.

Hamblin and D'Agostino share an embrace on the track to the delight of spectators. ( Reuters: Lucy Nicholson )

But that meant nothing to Hamblin, D'Agostino and the spectators in attendance, who cheered loudly as the pair embraced across the finish line.

D'Agostino left the track in a wheelchair as a result of the injury she sustained in the fall.

D'Agostino thanks Hamblin before the American is taken from the stadium in a wheelchair. ( Reuters: Lucy Nicholson )

Hamblin expressed her gratitude towards D'Agostino for helping her when she was clearly in distress herself.

"That girl is the Olympic spirit right there," Hamblin said.

"I went down, and I was like, 'What's happening? Why am I on the ground?'

"Then suddenly this hand on my shoulder, like 'Get up, get up, we have to finish this' and I was like, 'Yup, yup, you're right. This is the Olympic Games. We have to finish this'."

Hamblin said it was a moment she would never forget.

"I've never met this girl before, and isn't that just so amazing, such an amazing woman," Hamblin said.

"Regardless of the race and the result on the board, that's a moment that you're never ever going to forget for the rest of your life, that girl shaking my shoulder, like 'Come on, get up'."

Both Hamblin and D'Agostino were later added to the field for the final after New Zealand and US team officials lodged successful protests.

Australia's Eloise Wellings and Genevieve Lacaze celebrate making the 5,000m final. ( AP: David J Phillip )

Austria's Jennifer Wenth was also included in the final after she had been judged to have been impeded in the same incident.

Wenth had crossed the line in 14th place in 16:07.02.

Meanwhile, Aussies Wellings, LaCaze and Madeline Hills will all progress to the finals.