Recalling Patel's contribution in uniting the nation, Modi said the leader ensured "the merger of all princely states with the Dominion of India".
But around the statue in a remote corner of Gujarat state, more than 5,000 police guarded the huge site where construction work has taken almost four years to complete the mega project. Both Prime Minister Narendra Modi and Patel hail from Gujarat state.
Ram V. Sutar, a renowned sculptor from Noida, was the architect while Larsen & Toubro designed and executed the project using a team of over 3,000 workers and 250 engineers at a cost of Rs. 2,389 crore. Instead, he tore into the Modi government, saying it's "ironic that a statue of Sardar Patel is being inaugurated, but every institution he helped build is being smashed".
The statue's construction had received opposition from some tribal groups in Narmada district.
According to local media reports, at least 16 tribal leaders were detained on the eve of the inauguration.
"The Statue of Unity" project was announced by Modi back in 2010 when he was still the chief minister for the state of Gujarat.
Paul Pogba: Man Utd midfielder takes 26-step penalty against Everton
Manchester United bounced back from a disappointing week to beat Everton 2-1 at Old Trafford. It was a game we didn't need to suffer as much in the last few minutes.
The statue is more than twice the size of New York's Statue of Liberty and also dwarfs the 128m-high Spring Temple Buddha in China, the world's next-biggest statue.
Built by Larsen and Toubro, the Statue of Unity has been created to withstand winds of 180k/hour, akin to a category 3 storm, as well as 6.5 magnitude earthquakes.
Visitors can go up to the viewing gallery, which is located near the chest of the statue at a height of 153m.
"In order to build the Statue of Unity, lakhs of farmers from all over India came together, gave their tools, portions of the soil and thus a mass movement developed", he said.
Modi also linked Infantry Day - observed in commemoration of the first victorious military action led by the Infantry in Jammu and Kashmir after Independence to drive out Pakistani invaders - to Patel. The state government is building a two-mile high way for tourists to reach the statue from the nearby town of Kevadia, while it can also be reached by boat across the Sardar Sarovar reservoir.
Mr Modi will dedicate the statue on October 31, Wednesday.
- Statue's surface (skin) has 553 bronze panels - each panel has 10-15 micro panels - made at a Chinese foundry, as there was no facility available in India to make panels of this scale.