Chief Local Organiser Danny Jordaan said last week that officials would test noise levels at the refurbished 90,000 seat Soccer City stadium in Johannesburg when it was almost full for the first time during a friendly between South Africa and Colombia.
He had said there were concerns the trumpets, which sound like a herd of charging elephants, could drown out emergency announcements or be disrespectful during the playing of national anthems.
Asked about the tests on Tuesday at a news conference, Jordaan said: "Now the vuvuzela is in this World Cup. It is part of this World Cup."
FIFA President Sepp Blatter has also defended the trumpets, saying they are as much a part of football in South Africa as bongo drums or chanting in other nations.
Jordaan said fans would be asked not to blow the plastic trumpets during the national anthems but there would be no bans.
During last year's Confederations Cup, a dress rehearsal for this month's football spectacular, foreign players and managers complained about the din.
Thailand manager Bryan Robson said during a friendly against South Africa last month that he was unable to communicate with his players because of the trumpets, which he said could give South Africa an advantage during the World Cup.
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