New fencing and warning signs have been installed close to temporary flood defences.
It comes after people had been spotted dangerously "clambering over and fishing" from the defences in south Lowestoft in recent weeks.
A scheme of emergency maintenance work had been completed before Christmas as part of temporary protection to the base of eroding cliffs in Pakefield.
With the temporary beach protection work carried out to help support the vulnerable cliffs, sandbags have been installed"in a 100m length protection at the base of the cliff and beach south of Arbor Lane in Pakefield.
East Suffolk Council, through Coastal Partnership East - which manages the coast on its behalf - had appointed the Water Management Alliance (WMA) to carry out the temporary protection work that was completed in December.
The WMA had"extracted a small amount of beach materia" from Lowestoft South Beach, between Rectory Road and Kensington Road, which was then transported by dumper truck to Pakefield.
From here, several one tonne bags were filled before being placed at the base of the cliff and beach near Arbor Lane.
At the time, a spokesman said: "We have been working closely with the Pakefield Community Steering Group helping to protect homes and our beautiful and important coastline economically and environmentally and for the enjoyment of communities and visitors for generations to come."
But with people having been seen climbing on the temporary sandbags, further work has been completed in recent days.
An East Suffolk Council spokesman said: “The temporary defences were put in place to help support the vulnerable cliffs to the south of Pakefield, at Arbor Lane.
"Despite some very challenging weather over the Christmas period the defences have performed well.
"However, the community have noticed a number of people clambering over the defences and in some cases fishing from the top of them.
"This is dangerous," the council spokesman added.
"The cliffs are still unstable and people should not walk, climb, dig or sit on or close to them.
"Our contractors have installed the new fencing to deter people from climbing onto the temporary defences, damaging them or putting themselves in harm’s way.”
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