The NRL has threatened to strip Lottoland of finals hosting rights unless Manly address security concerns after a Sea Eagles fan lashed out at Melbourne's Will Chambers.

The NRL integrity unit has launched an investigation after the ugly incident marred the Storm's 36-6 win over the Sea Eagles at the northern beaches suburban venue on Saturday night.

Alarming breach: Security and police swooped on a Manly fan, centre, who confronted Melbourne Storm’s Will Chambers on Saturday night at Lottoland. Credit: Grant Trouville © NRL Photos

The incident highlighted the shortcomings at the ground as a fan wearing a Manly jersey attempted to reach through the players' tunnel to lash out at Chambers as the Storm centre left the field after being sin-binned.

NRL CEO Todd Greenberg said that unless improvements were made to the venue in the next two weeks, the Sea Eagles would not be allowed to host a finals game at their spiritual home.