The petition was sent on Saturday to Crown Prince Abd Allah bin Abd al-Aziz, the country's de facto ruler, as well as other senior Saudi figures.
It called for the recommendations of a "national dialogue" session in the Saudi city of Makka in late December, to be implemented with a priority-based timetable.
Backed by 800 signatories, who included woman activists and business people, the petition said this would "push the reform process forward", according to a copy received by AFP in neighbouring Bahrain.
The signatories singled out demands for "broadening public participation, electing the Shura (consultative) Council and regional councils," and creating trade unions and other institutions of civil society.
The petitioners also called for "renewing the religious discourse, entrenching a culture of dialogue and tolerance, combating extremism, guaranteeing freedom of expression, enhancing women's role in society ... and respecting intellectual and confessional diversity".
The so-called Convention for National Dialogue held a second round in the Muslim holy city Makka, in late December after a landmark meeting in the capital in June 2003.
Round two involved 60 Muslim clerics and intellectuals, including 10 women who took part in the deliberations via a video conference link, and who were joined by 15 researchers.
The first meeting held in Riyadh ended with a call for wide-ranging reforms and led to the establishment of a dialogue centre, which hosted the second round.
Saudi leaders promised in October 2003 to organise the first ever polls in the conservative kingdom within a year to elect half the members of new municipal councils.
Promises of reform come to the backdrop of an unrelenting crackdown by Saudi authorities on Islamists, blamed for a series of bombings in Riyadh in May and November 2003 that left more than 50 people dead.
Copies of the pro-reform petition, the latest in what has become a series of such approaches to Saudi leaders, were sent to top officials including Defence Minister Prince Sultan bin Abd al-Aziz, Interior Minister Prince Nayif bin Abd al-Aziz and Foreign Minister Prince Saud al-Faisal.