SAG prexy Melissa Gilbert and AFTRA president John Connolly have blasted management trustees of SAG’s health and pension plan for opposing the unions’ desire to merge the SAG and AFTRA plans.

“Our advice to members: Consider the source,” Gilbert and Connolly said. “We know we can’t rely on employers to look out for our best interests.”

The unusually strong attack underlines the high-powered campaign by union leaders to convince 98,000 SAG members and 77,000 AFTRA members to endorse combining SAG and AFTRA.

Members will vote next month on “consolidation” — forming an umbrella union with affiliates for actors, broadcasters and recording artists. The merger of the health and pension plans is a cornerstone of the campaign, since union leaders also have asked the trustees to lay the groundwork to merge the health and pension plans to hold down costs and improve operating efficiencies.

SAG management trustees found such a move will result in a “diminution of benefits and an increase in administrative costs.”

But Gilbert and Connolly accused those trustees of misinterpreting the Mercer Consulting study, citing its assertion that there are no “critical barriers” to combining the plans, and warned them the new union would seek to combine the plans over the objections of those trustees.

“If members approve consolidation, we intend to pursue this course of action — with or without the support of management,” they said. “It is in our members’ best interest.”

The missive from Gilbert and Connolly also blasted opponents within the unions for having adopted “the employer’s perspective as their own.”

SAG board member Tom Bosley, who opposes the merger, sent out an e-mail at a cost of $3,500 to members citing the management trustees’ concerns.

The management trustees have agreed to ask the SAG plan administrator to study the matter further and discuss it at its July meeting, after SAG and AFTRA members have voted on the merger.

The SAG plan operates independently of SAG with 36 trustees — 18 repping management and 18 for SAG. The plan and SAG have refused to release the 43-page Mercer report.