New mesh, higher fencing and more cameras will be installed on the Sydney Harbour Bridge in a bid to stop people from illegally climbing the landmark.
The NSW government will also increase six-fold the maximum fine to $22,000 - in line with the punishment for illegally scaling the Sydney Opera House.
The move follows a review of security measures after a mentally-ill man brought the city to a standstill when he climbed the bridge in April during an hours-long stand off with police.
Roads Minister Melinda Pavey acknowledged the bridge could never be 100 per cent "security proof" but said the new measures will help deter people "preparing to disrupt an entire city".
"We've listened to the community and we're going to deliver better security and stronger fines to send a message: don't hold this city to ransom," she told reporters on Monday.
"There is help out there but don't have your issues taken out on the rest of the community."
Roads and Maritime Services' Sydney executive director John Hardwick said the review found no issue with security guards but that more could be done to make scaling the bridge more difficult.
The new anti-climb mesh, higher barrier fencing and additional surveillance cameras are expected to be installed by the end of 2018.