Sunnyvale voted unanimously Tuesday to consider a sweeping range of election reforms, including public financing of campaigns, instant-runoff voting and limits on campaign spending and contributions.

The reforms were proposed after concerns over negative campaigning and possible undue influence by special interest groups in recent elections.

``I believe in a level playing field,'' said resident Warner Gans, who spoke in favor of exploring reform.

The council also voted to create a 15-member charter review commission that would evaluate, among other things, a plan to scrap the city's ``seat system,'' in which council candidates run for numbered, at-large seats instead of against the entire pool of hopefuls. Each council member will nominate two members of the commission -- which was last convened in 1991 -- with the last spot selected by the entire council.

Most California cities either elect candidates by geographical areas or have elections in which all candidates compete. Voters put the seat system in place in Sunnyvale in 1968, in part to ensure representation of all residents. Santa Clara voters passed a similar initiative in 1972.

Opponents of the system believe it limits options for voters because they might be forced to chose between two candidates they like for one seat, for example, and two that they dislike for another seat.

``I would like people who I would truly like to be on the council to be on the council,'' resident Becky Horton said, ``not to choose between the numbered seats.''

Supporters, however, say the seat system fosters more competition and debate and that it also better allows voters to differentiate between candidates.

The council also directed the city attorney to research spending and contribution limits, public financing of campaigns and instant-runoff voting. In instant-runoff voting, voters mark not only their first choice, but their second and third choices as well. If no candidate receives a majority of first-choice votes, the candidate receiving the fewest votes is eliminated. That candidate's ballots are then reassigned to the candidates marked as second choices. The process continues until someone has a majority.

Sunnyvale is one of the few cities in the area without spending limits -- which has fueled record amounts of spending in recent years -- and the council kicked off the process of rethinking that. Candidates who spent the most in each open seat last year won. Councilman Tony Spitaleri spent about $7 per vote he received; Councilman Chris Moylan spent about $4; and Councilman John Howe spent more than $3.

The Sunnyvale Public Safety Officers Association, for example, spent $17,000 within days of the election last November to back the three candidates it supported.

One concern about contribution limits is that they would give wealthy candidates an unfair advantage. Limiting the amount each group or individual can give to a candidate also might force the candidate to spend more time making phone calls to raise small sums of money instead of getting out to talk to voters.