Cities and towns will face a “staggering” increase in their pension fund contributions if the state Retirement Board votes Wednesday to accept a draft proposal by its actuary, according to Dan Beardsley, executive director of the Rhode Island League of Cities and Towns.

Beardsley, a longtime member of the Retirement Board, told WPRI.com on Monday he was shocked when he received the actuary’s report, which recalculated how much state and municipal taxpayers must contribute to Rhode Island’s pension fund in light of new investment and longevity forecasts that were approved last month.

The Retirement Board, which is chaired by General Treasurer Gina Raimondo, is set to vote Wednesday on whether to accept the new numbers – and the higher annual funding they will require. “My vote’s going to be the toughest vote I’ve ever had to cast in my 20 years on the Retirement Board,” Beardsley said.

The increase in pension contributions would take effect during the fiscal year that starts July 1, 2012.

Beardsley voted with Raimondo to approve the new forecasts at last month’s meeting, and said he did not regret doing so. “But it’s one thing supporting the right thing to do when it comes to dealing with … what goes into actuarial assumptions,” he said. “It’s another thing when the results come back and they’re staring you in the face.”

“The amounts are just staggering for some communities,” he added.

An alternative option the board may consider would be voting to “re-amortize” the long-term pension liability, or increasing the length of time over which it will be paid down, Beardsley said, though he emphasized that he does not necessarily support doing that. Critics say such a move would add too much to the total cost.