BOSTON – Las Vegas casino operator Steve Wynn is bankrolling an effort to convince Everett voters to support a proposed casino in the city, while nothing has been spent in opposition to the plan, according to campaign records.

A referendum is scheduled for Saturday on a host community agreement Wynn signed with city officials that calls for $30 million in advance payments to Everett and more than $25 million in annual payments if the casino was to open for business.

Supporters and critics of the plan say they anticipate voter approval of the agreement, marking a key step forward for Wynn in a casino selection process that will ultimately be decided by the Massachusetts Gaming Commission. Wynn has proposed a $1.2 billion casino on a 37-acre site along the Mystic River that once housed a chemical plant.

In a report posted by the state Office of Campaign and Political Finance, the pro-casino group Everett United, which is pushing for a yes vote on the referendum, reported $85,455 in contributions through June 4.