There have been a number of reported incidents at the pier in recent months - including regular instances of trespassing and a number of potential criminal damage cases, as fishermen and walkers have sought to enter the area while it has been locked.
The harbour master said trespassing incidents were occurring at the pier “on a weekly basis”.
He also said that heavy-duty tools, such as bolt-cutters and car jacks, had been used by trespassers to gain entry to the pier area in recent months.
A decision was taken to close the pier to the public during the first lockdown last year.
Unlike other public spaces that were closed as a precautionary public health measure in 2020, which have since re-opened, access to the pier remains restricted.
Police were called to a December incident at the North Pier, Tynemouth, which is being pursued as a private prosecution. The port authority has warned that trespassers at the South Shields pier could similarly face criminal charges.
“We’re having to put our security staff into a situation we don't want to put them in as a result of these incidents,” harbour master Steven Clapperton said.
"There’s also a potential criminal damage element to this, as we’ve seen incidents of people turning up with bolt-cutters and car jacks to damage what’s essentially a heritage asset.”
"We would consider enforcement action, if we found anyone out there now.
"The pier is a very dangerous place at the moment and our primary responsibility is ensuring people's safety."
The warning comes as residents voice their frustrations around the council’s decision to keep foreshore car parks open during Lockdown 3.
"We’ve taken a really strong position on workplace safety in line with the Government’s requirements, to make sure everyone’s able to stay safe,” Mr Clapperton added.
"The guidance is clear. We know that people won’t be able to keep two metres separate from each other on the pier and we can’t be part of increasing the risk of people catching coronavirus.
"So we’ve had to take this tough decision to close the pier, as it’s not possible to open in a Covid-secure way.
“I’m hoping we get to a more comfortable position by the end of March. It would be great to open up the pier again then and welcome everybody back.
"But for now I’d urge people to stay away. We need people to work with us on this.”