In February, the US Senate Judiciary Committee voted to advance Loretta Lynch's attorney general nomination, inching her closer to becoming the first African-American woman ever to hold the post.
Her nomination, currently pending before the full Senate, comes at a time of deep Republican animosity towards Obama's immigration reform plan, which he introduced by executive order in November.
"You don't hold attorney general nominees hostage for other issues," Obama told The Huffington Post online news outlet.
Lynch, 55, would succeed Attorney General Eric Holder, a polarizing figure for Republicans who accuse him of being a rubber stamp for Obama policies.
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Just this week, Senate Majority Leader Mitch McConnell said Lynch's nomination would not go up for a vote before the Republican-controlled Senate until the chamber passes human trafficking legislation.
Obama's fellow Democrats are opposing anti-abortion language in the measure.
The president rejected suggestions that race played a role in delaying Lynch's confirmation, blaming instead "Senate dysfunction" and "stubbornness on the part of Republicans to move nominees, period."
"Even the Republicans acknowledge she's been a great prosecutor.
"Her integrity is unimpeachable. By all accounts, she's a great manager... We need to go ahead and get this done."
Lynch earned high praise for cracking down on corruption and convicting terror suspects in her position as chief US attorney for the Eastern District of New York.