Kenyan world record breaker Faith Kipyegon has helped Australian star Jessica Hull into uncharted territory in the women's 1500m at the Diamond League athletics meet in Florence.

Kipyegon put in a blistering last lap to obliterate the world record with a time of three minutes 49.11 seconds on Friday night (early Saturday AEST).

Hull and Britain's Olympics silver medallist Laura Muir were the only other runners able to go with the Kenyan when she turned up the heat in the middle stages of the race.

Muir claimed second spot in 3:57.09 and Hull was a gutsy third in 3:57.29, stripping more than 1.5 seconds off her previous Australian and Oceania record set two years ago at the Tokyo Olympics.

"It was pretty obvious from the start that Laura Muir was going to want to go quick so I followed her. I looked up at 500m in and thought it was a bit hot for me," Hull said.

"I was caught in no-man's land when I was out there but instead of being in my own head, I just got back into the race plan and fought well. I kept my eye up on Laura and found my legs again.

"It was pretty crazy to be part of a world record race and I didn't realise what had happened because I was wrecked when I was finished.

"We all respect Faith so much and it seems right that she has the world record now because she truly is the greatest and it's really exciting to be part of it."

The 26-year-old Hull continued her impressive start to 2023 which has included bronze in the mixed relay at the world cross country championships and a treble of national titles in the 1500m, 3000m and 5000m.

The third placing at the Golden Gala meet behind the extraordinary Kipyegon will also boost Hull's hopes of breaking through for a first major global medal at the world championships in Budapest in August.

Fellow Australians Abbey Caldwell (4:01.34) and Linden Hall (4:02.43) were sixth and 10th respectively.

After running solo at the front in the final lap, two-time Olympic gold medallist Kipyegon smashed the previous world mark of 3:50.07 set by Ethiopia's Genzebe Dibaba back in 2015.

The other standout Australian performance of the evening in Florence came from world championships bronze medallist Nina Kennedy, who was third in the women's pole vault.

Kennedy had a successful first-time clearance at 4.61m in a competition won by American world and Olympic champ Katie Moon.

"I was feeling good attempting 4.71m," said Kennedy.

"I had some pretty big height over it, but there are so many factors in pole vault that everything has to align.

"It didn't align tonight unfortunately but there were some really promising signs for the next couple of months."

Rohan Browning was sixth in the men's 100m in 10.15, with American world champ Fred Kerley (9.94) extending his unbeaten run in 2023.