The Cambridge Town Cup rowing regatta at Lake Karapiro has thrown up two early season shocks.

National quadruple sculler John Storey has defeated Olympic champion Mahe Drysdale in the men's single scull, while Rebecca Scown and Genevieve Behrent have set an unofficial world's best time in the women's pair.

Rowing does not have world records because of the irregular nature of current flow in the rivers and lakes hosting regattas, like Karapiro.

Storey took advantage of tailwind conditions to pip Drysdale by 1.65s.

The 28-year-old time of six minutes 35.57 seconds was 2.22s outside Drysdale's world best, set at Poznan in 2009.

Storey has been around the Rowing New Zealand elite scene since 2010. His best international result came in the quadruple sculls at the London Olympics when the crew finished seventh.

At last year's world championships in France, his crew missed qualifying for the Rio Games by one spot - they finished ninth - but get a last opportunity to secure two remaining spots at the regatta of death in Lucerne during May.

The result further complicates a difficult summer for Drysdale after the well-documented spat between his coach Dick Tonks and Rowing New Zealand. The relationship breakdown potentially left him coachless for the Olympics. It has since been resolved, with Tonks continuing as his mentor.

Scown and Behrent recorded a time of six minutes 49.06 seconds to defeat world championship silver medallists Kerri Gowler and Grace Prendergast.

Their effort beat the previous world best of Olympic champion Brits Heather Stanning and Helen Glover by 1.55s.

It requires ratification from international governing body Fisa's records team - when they wake up in Lausanne.