Fellow Ballarat Project athlete Selma Kajan followed it up as part of a new Australian women's 4x800m record in the IAAF World Relays in the Bahamas.

Birmingham and Gregson teamed with Sam McEntee and Jordan Williamsz to clock a time of 14 minutes, 46.04 seconds and finished fourth in the IAAF World Relays in the Bahamas.

The Ballarat-based duo were also part of the Australian record they broke, set in 2009.

Kenya won the event in world record time - 14:22.22.

Birmingham, running the third leg, powered Australia into third place with a split of 3:38.3, before anchor Williamsz was edged out by Ethiopia in the final two laps.

He entered the inaugural world relays on stellar form in the United States the past month.

This includes a Commonwealth Games 5000-metre qualifying time in a shock upset win against American Olympic 10,000m silver medallist Galen Rupp in Los Angeles last weekend.

Gregson, who clocked a 1500m qualifying time for Glasgow in the same meet, was also part of a new Australian 4x800m relay record on day one in Nassau.

Gregson teamed up with Joshua Ralph, Jordan Williamsz and Jared West to clock a combined time of seven minutes, 11.48 seconds to finish fourth to Kenya, which won the men’s 4x800m title in 7:08.40, a Commonwealth record time.

Kajan and the Australian 4x800m team, featuring Moscow world championship 1500m finalist Zoe Buckman, clocked a national and Oceania record time of 8:13.26.