An estimated two million people are expected to descend on Rome in the coming days ahead of the funeral of Pope John Paul.
Extra trains and fresh water supplies have been organised and a tent city is being erected ahead of the funeral.
An estimated 200,000 people streamed into St. Peter's Square throughout the day yesterday to show their respect for the Polish Pope who led the Catholic Church for over a quarter of a century.
The attendance of scores of heads of state for the funeral will add to the unprecedented strain on the Italian capital.
Interior Minister Giuseppe Pisanu mobilised 6,430 security forces and said the foreign ministry's "crisis unit" would help bolster protection for visiting dignitaries.
Mayor Walter Veltroni warned that Rome faced one of the biggest organisational tasks in its history, surpassing even the Catholic Jubilee Year in 2000 when 30 million pilgrims crammed into its cobbled streets over a 12-month period.
For the Pope's funeral alone, officials are expecting at least two million pilgrims, far outnumbering the 250,000 that filled St. Peter's Square for Mother Teresa's beatification in 2003, among the most popular events of John Paul's pontificate.
Regional railway authorities reported a 30 per cent increase in arrivals in Rome. The city's two main airports said they expected a heavy flow of visitors from today.
Workmen have begun building "tent cities" in sports venues like Rome's Olympic Stadium yesterday to accommodate the visitors. Huge television screens to show the funeral went up at 10 sites.
In the Pope's home country of Poland, there has been a scramble for transport services bound for the Vatican.
Within 15 minutes of extra Rome-bound trains being announced, one million people accessed the state railway website causing it to collapse.
National air carrier LOT said all flights to Rome were sold out between now and Friday and is in talks with Rome airport operators to offer more flights.
At St Peter's Square this afternoon, people poured into the piazza to see the Pope's remains which are due to be on display later today.