A key Republican senator says she is concerned about how an Obamacare overhaul bill would affect her state.

Sen. Lisa Murkowski of Alaska said she remains undecided on a bill to turn Obamacare funding into block grants. The four Republican senators touting the bill say that it would give states added flexibility in how they structure healthcare coverage.

The bill would give states $1.2 trillion from 2021 to 2026. States that expanded Medicaid under Obamacare would receive less funding initially than non-expansion states, although eventually the two groups of states would receive the same base rates. Alaska expanded Medicaid under the Afforeable Care Act.

Murkowski, who voted against prior Obamacare repeal bills, had major questions about the funding formula.

"We understand what block grants do, but if we get more flexibility without enough money to utilize the flexibility, that makes a difference," she said Monday.

Murkowski said she is working out the details of the bill, co-sponsored by Republican Sens. Lindsey Graham of South Carolina, Bill Cassidy of Louisiana, Dean Heller of Nevada and Ron Johnson of Wisconsin.

Republicans hope to hold a vote on the bill by Sept. 30, the deadline to use a procedural tool called reconciliation that allows a bill to be approved with a simple majority and bypass a filibuster.

The Congressional Budget Office said it would provide a "preliminary assessment" by early next week of the proposal.