Avalon and Ocean City were keeping visitors out of the water and away from the wet sand at least through the afternoon.
Only a day earlier, Ocean City banned swimming on part of its beach after at least two syringes were found on the sand. Earlier in the week, nearly 200 syringes washed up in Avalon, prompting the town to close some of its beaches throughout the week.
Avalon town spokesman Scott Wahl said six more syringes washed ashore on Friday, but said the needles weren't similar to what washed up earlier in the week.
The nature of the Ocean City waste wasn't immediately clear.
State officials on Friday were tracking serial numbers from the Avalon syringes, and were offering a $10,000 reward for information leading to the arrest of those responsible for dumping the waste.
Environmental activists say the discovery of syringes in Avalon is one of the worst single cases in years of medical waste washing up on the shore. In the 1980s, when thousands of beach-going days were lost because of waste washing ashore, and that discovery sparked a ban on trash dumping off the New Jersey coast.
Thousands of visitors are expected to travel to the Jersey shore for the Labor Day weekend.