The insurer's survey found that 65% of women think their financial planning needs improvement, while 54% of men felt that way. Women are more likely to consider themselves "informal" planners than men -- 41% vs. 35%.

"Perhaps most strikingly -- despite having longer life spans than men, women feel less financially prepared to reach age 75 (48% vs. 65%), 85 (37% vs. 55%), and 95 (30% vs. 43%)," Northwestern Mutual said.

While women are more likely to feel their planning needs improvement, they're approaching their finances more cautiously than men, the study found. Far and away, for both men and women, the most preferred approach to saving and investing is "slow and steady wins the race," with 36% favoring that approach. Women are more likely to have a strong preference for safe but lower returns with very low risk, over high returns with high risk than men, according to the study.

However, among Americans taking steps to become more financially secure in 2012, women are more likely to make "building up an emergency fund" a financial priority -- 61%, compared with 54% for men.

"There are some good signs here -- particularly in women's recognition that their financial planning needs more attention," said Rebekah Barsch, a Northwestern Mutual vice president. "But as is the case with everyone we surveyed, not just women, there is a distinct need to bring more focus and discipline to the financial planning process."

Other findings of the Northwestern Mutual study:

• 62% of Americans are taking steps to pay down their debt, while 61% are developing a budget.
• 58% of Americans save a portion of their paycheck regularly and build up an emergency fund.
• Americans ages 25 to 59 feel less prepared than older Americans, those 60 or more, to live to 75 (47% vs. 79%), to 85 (37% vs. 66%) and to 95 (29% vs. 52%).

Northwestern Mutual sponsored a series of studies to evaluate the state of financial planning in America and people's progress toward reaching their long-term financial goals. Independent research firm Ipsos conducted the online survey of 1,015 Americans age 25 or older between Feb. 2 and Feb. 13 via a systematic random sample of U.S. adults. Results were weighted as needed to U.S. Census proportions for age, gender, marital status, household size, region and household income.