Torrey Pines, the famed San Diego public course where next months US Open is set to be played, is stepping up it's security after it's signiture hole was vandalized for the 2nd time in a month.

Workers arriving on Sunday found a vulgarity scratched into a sand trap beside the South Course's third green, it's most photographed, along with several broken sprinkler heads.

Earlier, in May, another, more damaging act of vandalism at the same hole, saw an obscenity scraped into the surface of the green.

The City's golf manager Mark Woodward says the damage from both incidents was relatively easy to repair, but confirmed that the acts of vandalism had put the course's manager on high alert and had resulted in a fence being erected near the green and a set of powerful, portable searchlights being installed.

The US Open, which is expected to feature all of the world greatest players, including Tiger Woods who believes he will have fully recovered from his recent knee operation by then, tees off on Thursday June 9.