Sunday's inauguration and the ongoing makeover of the heart of New Delhi based on Indian culture, traditions and symbols come a year before parliamentary elections in which Modi's Bharatiya Janata Party (BJP) will pitch its strong Hindu nationalist credentials, besides its performance in office across the past decade, to seek a third term.
The Modi government has also similarly renovated some of Hinduism's most revered pilgrimage centres since first sweeping to power in 2014.
The new, triangular-shaped parliament complex is just across from the heritage building built by British architects Edwin Lutyens and Herbert Baker in 1927, two decades before India's independence.
The old parliament will be converted into a museum, the government has said.
It has said a new parliament building is badly needed as the existing structure "is highly stressed" for a number of reasons including capacity, infrastructure, technology and safety.
The new building, Modi said when he launched its construction in December 2020 during the pandemic, "would become a witness to the creation of a self-reliant India", underlining another pet theme.
Besides modern technology, the new parliament has a total of 1272 seats in two chambers, almost 500 more than the old building, and at least three times as much space.
It features four storeys and halls themed according to the national symbols of the peacock, lotus and banyan tree, and murals, sculptures and art from across the country capturing 5000 years of Indian civilisation, an architect directly involved in the project said.
But critics of Modi see the new parliament, designed by an architect from his home state of Gujarat, as an attempt to bolster his brand of nationalism as part of a personal legacy.
Opposition parties have announced a boycott of the inauguration.
The president, the highest executive of the country, should open the new parliament and not Modi, the opposition members said.
The president's office declined to comment.
An official in Modi's office said the prime minister respects the constitutional head of the country.
On Friday, the Supreme Court dismissed a public interest petition that sought a direction from the court to get the president to inaugurate the building instead of Modi.
The overall makeover includes the new parliament, the construction of several government buildings along the lawns of India Gate in the centre of the city and new residences for the vice-president and the prime minister.
The plan has drawn objections from conservationists and urban planners who say it will obliterate the character of the city.
"The decision to build a new parliament building was abrupt and there has been no transparency, probity and frugality in the entire process," said AG Krishna Menon, an architect and conservation consultant.
