Howth Coast Guard has advised the public to avoid walking on the East Pier in Howth between 10am and 4pm today due to expected waves breaking over the pier wall.
Outside these times, people should be cautious and use common sense.
Meanwhile, DART services through Blackrock are facing delays of up to 15 minutes due to high waves over the sea wall affecting signalling equipment.
Howth Coast Guard said: "If you see the spray of the waves reaching on the pier don't walk it. Waves can be unpredictable, a lull of ten minutes can be followed by intense waves powerful enough to knock you over and cause injury or wash you off the pier wall."
High waves broke over the pier wall yesterday, and the Coast Guard responded to calls about people going under the waves to take photographs.
It says people doing this not only put their own lives at risk, but also endanger the lives of Coast Guard and RNLI workers.
The Coast Guard added: "We ask the public to call the Coast Guard at 112 or 999 if they see people who are likely to get into difficulty, don’t expect someone else to make the call."
