US Senator Max Baucus said Tuesday he will not seek re-election in 2014, making him the latest senior Democrat to avoid a tough bid to hold his seat in a conservative-leaning state.

The retirement of the six-term senator from Montana, who heads the powerful Finance Committee, will provide one of several opportunities for rival Republicans to capture a seat in the 100-member chamber.

Baucus, 71, joins five other Democrats who are retiring from the Senate next year, including Frank Lautenberg of New Jersey, Carl Levin of Michigan and Tom Harkin of Iowa. The Montana seat is seen as among the most difficult to defend next year.

"After much consideration and many conversations with my wife Mel and our family, I have decided not to seek reelection in 2014," Baucus said in a statement.

"In the next year and a half, I want to spend all my hard work, shoe leather and luck working for the people of Montana instead of on campaigning."

Democrats currently control the Senate 55-45, with that majority figure including two independents who caucus with Democrats.

But with several veteran Democrats announcing they will retire rather than face a bitter re-election fight, Republicans have spoken openly in recent months about the improved prospects of winning back the Senate in the November 2014 mid-term elections.

Baucus in recent months proved to be a thorn in the side of President Barack Obama's gun control initiatives, voting last week against a landmark measure to expand background checks on gun purchases.