Some 2.5 million people are expected to take in more than 90 light and sound installations scattered across the city during the 23-night annual festival, the world's largest of its kind.
While there has been no direct threat to Vivid, authorities are eager to reassure visitors, many of them tourists, following the bombing at a pop concert in Manchester on Monday that left 22 dead and dozens injured, many of them children.
A "high-visibility policing strategy" will see extra officers patrolling with "firearm explosive dogs" carrying out searches.
"We have police in the air, we have police on water and we have police on the ground," New South Wales state Assistant Police Commissioner Mick Fitzgerald told reporters.
"We are very very confident we have sufficient resources in place."
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Artists from around the world will be in Sydney for the festival, with more than 400 music events scheduled alongside the light installations and projections, including giant sea creatures beamed onto the Sydney Opera House's iconic sails.
"Tourists can be incredibly confident, as can locals, in visiting Vivid to enjoy themselves and to do so knowing that every resource possible has been deployed to look after their safety and welfare," said New South Wales major events minister Adam Marshall.
Australian officials say they have prevented 12 terror attacks on home soil since 2014 with 61 people charged.
