The 19-year-old covered an impressive 56.36m with her throw at the Hayward Field last night in the World Junior Championships.
Her previous best was 53.97m which she recorded while winning the Junior Federation Cup at Chennai this May, a release stated.
Brazil's Izabela da Silva set a world junior leading mark of 58.03m for the gold while American Valarie Allman (56.75m) entertained the home crowd with a silver medal.
Incidentally Seema won a gold medal in 2000 at Santiago de Chile, but was disqualified thereafter due to doping violations.
Navjeet's first major success came in Commonwealth Youth Games at Douglas (Isle of Man) in 2011 when she won a bronze medal with a throw of 45.27m.
Last year she had taken part in the senior category in Asian Grand Prix and was placed seventh in the Asian Championships at Pune.
In the Junior Federation Cup this year, Navjeet set a new national junior record in shot put (15.89m) besides winning a "double" through a victory in discus throw with a noteworthy 53.97m.
Navjeet is also the reigning Inter-University champion.
