Senate Republicans signaled Tuesday they would seek to repeal the Affordable Care Act requirement that most Americans must have insurance coverage as part of their tax-overhaul package, adding an uncertain element to an already complex legislative effort.

The package is expected to be released later Tuesday. GOP Senate members met to discuss the repeal measure, which President Donald Trump has said should be part of the tax plan.

GOP leaders have been cautious about bogging down the tax bill with controversial health-care provisions, but have been suggesting they could include the repeal because it would generate revenue that could be used to pay for tax cuts elsewhere.

Senate Majority Leader Mitch McConnell (R., Ky.) said it would be part of the tax bill. “The Senate Finance Committee has decided to include that,” Mr. McConnell said.

Sen. John Thune (R., S.D.), a member of the Senate Finance Committee, said Republicans intend to use the savings generated by repealing the individual mandate to lower taxes for middle-income households. “It’ll be distributed in the form of middle-income tax relief,” he said.