"Each case will be examined in stages," the minister said, without giving a date for the start of the trials being held in the Saudi capital Riyadh.
US-based Human Rights Watch said it was seeking authorisation from the Saudi authorities to send observers to the trials, saying justice must be seen to be done.
OPEC powerhouse Saudi Arabia has faced a string of attacks against Western targets and oil facilities since May 2003 and hundreds of suspected Islamist sympathisers have been arrested.
Giving a first-ever official toll, Prince Nayef said the wave of attacks in the ultra-conservative Muslim kingdom had killed a total of 90 civilians — both foreigners and Saudis, and 74 members of the security forces.
He said 657 members of the security forces and 439 civilians had been wounded in the attacks, adding that security forces had foiled more than 160 "terrorist operations".
Three tonnes of explosives and more than 25 tonnes of possible bomb-making materials had been seized.
HRW said it was seeking permission from Riyadh to attend the trials of 70 defendants who were in court on Monday for the first time "to face charges of acts of domestic rebellion".
"Neutral observers should monitor trials of such national and international importance," Kenneth Roth, executive director of the New York-based group, said in a statement.
"For justice to be done, it has to be fair, and to be seen as fair."
HRW said it has written to Saudi Foreign Minister Prince Saud al-Faisal seeking authorisation to enter the country for the trials.
The Saudi daily Asharq Al-Awsat said tight security measures have been put in place around the Riyadh courthouse. Six judges have started work and another six are to be appointed for the trials, expected to last several months.
Al-Qaeda leader Osama bin Laden was born in Saudi Arabia although he has since been stripped of his nationality. Fifteen of the 19 plotters of the September 2001 attacks in the United States were Saudis.
HRW said Saudi Arabia, which has no written penal code, held about 3,000 suspected militants in its intelligence detention facilities for years without charge or access to legal counsel.
In November 2007, it freed 1,500 suspects after a re-education programme, it said. "Hundreds of new suspects, possibly more than 1,000, have been arrested since, however, leaving between 2,000 and 3,000 suspects in detention."
