The 50- by 100-metre zone was cordoned off "not because Tina Turner wants this (but) to avoid many boats" crowding near the manor in Kuesnacht, on Lake Zurich, police spokeswoman Esther Surber told AFP.
To frustrate sailing paparazzi, wedding organizers have erected a red canvas screen at the foot of the lakeshore garden.
Turner, 73, and Bach, 57, officially married in a discreet civil ceremony earlier this month in Kuesnacht, which lies on Lake Zurich's posh Goldkueste (Gold Coast).
They will celebrate the union Sunday in a Buddhist ceremony to be attended by some 120 guests including music industry A-listers David Bowie, Eros Ramazzoti and Sade as well as television talk show queen Oprah Winfrey, according to local media reports.
The Sunday paper SonntagsBlick published photos of Winfrey jogging in Zurich.
Schweiz am Sonntag weekly said the guests were requested to wear white, while the bride herself, who traded in her US passport for a Swiss one earlier this year, will wear a gown designed by Italian fashion giant Giorgio Armani.
Swiss media reported that a small stage would be set up for Sunday's party, and that Turner and Bach had sent out letters to their neighbours apologizing in advance for any disturbance they might cause.
SonntagsBlick said some 70,000 roses and orchids would decorate the villa.
Turner, born Anna Mae Bullock in Tennessee, was the voice of such hits as "Simply the Best" and "We Don't Need Another Hero" over a career spanning five decades, and moved to Switzerland in 1995 when Bach was transferred to the country.
Before her relationship with Bach began in the mid-1980s, Turner was famously married to her musical partner Ike Turner for 14 years.
She left him in 1976 after suffering serious domestic abuse, as detailed in her autobiography "I, Tina," and alluded to in her 1984 hit "What's Love Got To Do With It."
Tina Turner retired from the public eye after a final tour in 2008-09.