The Metropolitan Police said it would be imposing the Section 60 order across the annual event’s geographic area between 9am and 11.59pm on Sunday.
This means police are able to search people they believe may be carrying offensive weapons or in anticipation of violence.
It comes after hundreds of shops and homes were boarded up in the wealthy west London neighbourhood to avoid destruction over the bank holiday.
Metal-detecting knife arches are being installed for the first time and will be placed at “strategic points” along the route of the west London street party – but not everyone will have to go through them.
Last year, police made around 313 arrests for a range of offences, including 112 for drugs and 58 for offensive weapons. Twenty-eight officers were injured in total.
Dave Musker, Notting Hill Carnival gold commander, said he authorised the Section 60 order following a recent surge of violence in the capital.
“Given the intelligence picture and incidents of violence I have seen across the city over the last week, I have made the decision to authorise this order as an additional preventative measure,” he said.
“The use of this authority will reassure our communities that we are constantly working to protect them. It will also send a message to those intent on committing acts of violence that we will robustly target them.”
Police hope the “tried and tested” method will stop people arming themselves with weapons.
The two-day event – which has taken place over the August bank holiday since 1966 – will be policed by the highest number of officers in six years.
There will be 6,100 on-duty officers on Sunday’s less busy family day, while almost 7,000 officers will be policing Monday’s event to “combat the threat of violent crime”.
London has experienced a surge in street violence this year, with the number of knife and gun offences on the rise.
Around 82 people are suspected to have been deliberately killed since the start of the year.
The amount of acid attacks has also increased, with police previously revealing that the UK has one of the highest number of recorded acid attacks per person of any country in the world.
Three people were injured when an acidic liquid was thrown over them at last year’s Notting Hill Carnival event.
But the overall number of arrests was lower than in 2016, when more than 450 people were detained across the event.
This year’s carnival is expected to attract more than a million revellers to its floats, food stalls and music. It is led by members of the British West Indian community and is one of the largest street festivals in the world.
The music is scheduled to stop for a 72-second silence in tribute to the 72 people who died in the Grenfell Tower fire in June 2017.