United States-based athlete Julia Ratcliffe has extended her New Zealand hammer throwing record at a meet in New Jersey.

Throwing for Princeton University at her home venue, Ratcliffe threw 68.80m to better her previous mark of 67.00m set at the world junior championships last year where she placed fourth.

Former Hamilton athlete Ratcliffe, 19, needs to throw another 70cm further to reach the B selection standard of 69.50m for this year's world championships in Moscow.