Fewer than half of likely California voters support the state’s proposed high-speed rail project at its current price tag, according to a poll released Wednesday.

In 2008, 52 percent of voters backed a $9.95 billion bond measure for the high-speed rail network. However, the projected cost of the plan has gone from $34 billion to $68 billion since then.

The more expensive plan has residents wary, as only 43 percent of the 1,138 likely voters interviewed said they would support the project at its current cost, according to the Public Policy Institute of California poll.

The institute’s president, Mark Baldassare, said the majority of opposition to the project came from residents who expressed skepticism about the long-term economic prospects of California.

In total, about $11.5 billion has been secured for the project, meaning an additional $57 billion is still needed. Backers of the plan said the federal government and private investors can make up the shortfall.

Construction on the first segment of the project is scheduled to begin this year in the Central Valley. The fully built-out network from San Francisco to Los Angeles isn’t forecast to be completed until 2028.

wreisman@sfexaminer.com