Saudi Arabia's King Abdullah will address the nation on Friday, amid reports of a possible government reshuffle.
Diplomats said that among measures to be announced are ministerial changes and an anti-corruption drive, according to Associated Press.
The country has not seen the kind of unrest experienced by some of its neighbours in recent months.
But there were more small protests on Thursday in the eastern city of Qatif.
Hundreds of people reportedly gathered to demand the withdrawal of Saudi forces from neighbouring Bahrain, where they have been used in the suppression of pro-democracy demonstrations.
The protesters also called for the release of Shia prisoners held in Saudi jails.
The east of the country is where many of Saudi Arabia's Shia minority live and it borders Bahrain, a Shia-majority kingdom ruled by a Sunni government which has been rocked by protests in recent weeks.
Signs of dissent are not restricted to the Shia community but a planned "day of rage" by pro-democracy activists last week appears to have been prevented by a heavy security presence on the streets.
King Abdullah, 86, will issue a number of decrees in his speech after Friday prayers, the state news agency announced.
No further details were given but diplomats quoted by AP said the ministers of defence, higher education and religious affairs were to be replaced.
In addition, the diplomats said a new institution to combat corruption would be announced, and an increase in subsidies for basic foodstuffs.
King Abdullah unveiled a package of $37bn (£22.7bn) in benefits for Saudi citizens when he returned to the state last month, after having medical treatment abroad.