Despite widespread fears that the new tax changes will hurt charitable giving, millionaires plan to give the same or more than last year, according to a new survey.

The CNBC Millionaire Survey, conducted by Spectrem Group, found that two-thirds of millionaires plan to give the same amount to charity this year than they have in the past. About 20 percent plan to give more, and just 14 percent plan to give less.

The semiannual survey is representative of the affluent population in the United States. The survey analyzes the investment attitudes and behaviors of 750 investors with $1 million or more of investable assets. Respondents are required to be the financial decision-maker or share jointly in financial decision-making within the household.

The findings come as many nonprofits worry that the new tax law will make it less attractive for some families to give, since many will opt to take the new, higher-standard deduction rather than take charitable deductions. While it may reduce giving by middle- and lower-income families, the wealthy may actually give more, since many will lose other deductions, like state and local taxes.

Among the millionaires who are giving more, the largest number (26%) said it was because their incomes went up, while 21 percent said it was because of changes to the tax law and because of "the current political climate."

Among those giving less, the largest number (49%) said it was due to changes in the tax law.

Still, millionaires say they generally don't give for tax reasons. When asked about how much of a role taxes play in their giving, half agreed that while it's a benefit, it's not the "primary reason" they give. A third said it plays no role, and only 16 percent said it's a "significant reason."

Most millionaires don't plan to spend the savings from the tax plan, which could limit its broader economic benefits. Half plan to invest their tax savings, while another 26 percent plan to save it. Only 14 percent plan to spend it.