Salem Ben Mohammed al-Balahid, a Saudi Interior Ministry official, told local newspaper Okaz that 1.1 million pilgrims had arrived from abroad so far.
The Hajj pilgrimage, which has drawn two million Muslims in recent years, officially begins this year on 8 January.
It begins in the early hours when pilgrims who have assembled at Islam's holiest city of Makka in the western part of the oil-rich kingdom will set off on foot or by bus to Mina, an arid valley about 10km away.
Then devotees will spend the day in prayer and contemplation in the valley, where a massive number of fireproof tents are erected for shelter.
The next day at dawn, pilgrims will make their way towards Mount Arafat, where they assemble on the hilltop to pray and ask for God's forgiveness.
Reaching the summit
The act of reaching the summit symbolises the final judgment at the scene of the Prophet Muhammad's last sermon 14 centuries ago and marks the climax of the pilgrimage.
The faithful then return to Makka for the first day of Eid Al-Adha, or Feast of the Sacrifice, which will be celebrated on 10 January this year.
Most will sacrifice an animal, usually a sheep, in remembrance of Abraham's readiness to sacrifice his son - whom Muslims believe was Ishmael - to God.
Then the pilgrims will return to Mina to stone the "jamarat", or three pillars symbolising the devil - the final but also the most dangerous ritual.
All Muslims who have the means are required to complete the rites of the Hajj, or pilgrimage, at least once in their life time.