Members of the Democratic City committee of Cambridge said yesterday they expect a tight battle between reform and conservative elements in today's Committee election of candidates for the city Election Commission.

The Democrats' eleven ward committees will choose from a slate consisting of conservative incumbent Francis R. Burns and four reform challengers. City Manager James L. Sullivan will then appoint one of the three to the Election Commission.

The Election Commission supervises registration and voting procedures for all City Council elections.

A committee member who asked to remain anonymous said yesterday that the reformers will have to sweep the slate to get a chance at appointments. "Otherwise, you can be damned well sure that he [Burns] will be appointed," he said.

The committee member said that for political reasons Sullivan would bow to the wishes of the City Council, which has a 5-4 Independent majority, and select the incumbent conservative.

Mary E. Preusser, 1974-5 chairperson of the committee, said yesterday that Burns candidacy would not be hurt by allegations of voting fraud in the recent City Council election, and that few voters had even heard of the charges.

At the time of the Council election Burns was the Executive Secretary, or presiding member, of the four-man Electoral Commission.