Fifty-six percent of Americans think the stock market is too risky for Social Security funds, according to a Newsweek poll released on Saturday.

The poll signaled a tough sell for President Bush as he promotes his plans to change Social Security and allow workers to shift part of their payroll taxes into private stock and bond accounts.

The 56 percent who were wary of putting retirement money into the stock market contrasted with 36 percent who said such investing was a “necessary risk to improve the rate of return of Social Security funds.”

Bush made his bid to remake the 70-year-old Social Security program the centerpiece of his State of the Union address on Wednesday. Then he set off on a two-day trip to pitch his plan in North Dakota, Montana, Nebraska, Arkansas and Florida, all of which supported him in the November election.

Social Security provides benefits to 45 million Americans, and millions more are nearing retirement.

Bush bases his case for change on his contention that Social Security is headed for bankruptcy — a characterization that Democrats say exaggerates the problem and amounts to a scare tactic.

The Newsweek poll did show that 65 percent of Americans agreed with Bush that Social Security faces a crisis. But they were split on what to do about it.

Thirty-six percent of those surveyed opposed Bush’s proposals, 26 percent approved them, and 30 percent said they were not aware of them.

In addition to private accounts, Bush said he thinks there should be “permanent” changes made to the structure of Social Security to improve its financial viability and said he was open to ideas such as limiting the future growth of benefits.

The Newsweek poll was conducted on Feb. 3-4 for publication in the magazine’s Feb. 14 issue. The poll included 1,009 adults.