The wedding of a scion from India's ultra-wealthy Ambani family - much in the news for its opulent celebrations and VIP-studded guest list - has suddenly developed more political overtones with posters of Prime Minister Narendra Modi now lining the road to the venue.

The four-day extravaganza will see Anant Ambani, 29 - the youngest son of Asia's richest person Mukesh Ambani - marry his long-time girlfriend Radhika Merchant, 29 on Friday, followed by three days of receptions.

"Heartfelt welcome to India's beloved and respected Prime Minister Narendra Modi in Mumbai," read the dozens of posters recently erected by his ruling party workers along the road to Ambani's Reliance Industries-owned Jio World Convention Centre.

While attendees to the nuptials are expected to include reality TV star Kim Kardashian, former boxing heavyweight champion Mike Tyson as well as former British Prime Ministers Tony Blair and Boris Johnson, Modi's name had not figured on the guest list shared by organisers.

Modi is visiting the Mumbai area to inaugurate "a project" and may briefly attend the Ambani wedding, said Manoj Shinde, a police official from the traffic department of the Bandra Kurla Complex district where the venue is located.

The posters were not installed by Modi's party but may have been put up by some "excited party workers", said Keshav Upadhye, the state's chief spokesperson of Modi's ruling party.

Modi has faced much criticism from Indian opposition leaders who say he is too close to tycoons like Ambani, allegations that the prime minister and his government have denied.

The wedding has been deemed a public event by local officials due to the attendance of so many international and local celebrities, politicians and business leaders.

That's meant traffic in the area has been closed to the public for most of the day for four days - raising the ire of locals in Mumbai - a city plagued by traffic congestion, especially in the monsoon season.

The estimated millions and millions of dollars spent by Ambani on the months-long celebrations - which have seen pop stars Rihanna and Justin Bieber perform at pre-wedding events, have also triggered debate in a country where income inequality has been rising.

Though some proponents have said the events are boosting the economy and help generate business for many citizens, others like Indian opposition politician Thomas Isaac have called the amount of spending "obscene".

"Legally it maybe their money but such ostentatious expenditure is a sin against mother earth and (the) poor," he said in a post on X.