In this June 28, 2013 file photo, Wisconsin Gov. Scott Walker speaks in his Capitol office in Madison, Wis. (AP Photo/Scott Bauer, File)
Walker's locked in a tight race with Burke. (AP Photo/Scott Bauer, File)

The Republican Governors Association has purchased more than $1 million in additional television advertising time in Wisconsin to boost embattled Gov. Scott Walker, who is locked in a close race against Democrat Mary Burke.

According to two senior RGA officials who requested anonymity to speak freely about strategy, their original plan had been to spend about $900,000 on the Wisconsin airwaves in the campaign’s closing days. But after internal deliberations and tightening polls, that amount has been increased to $2 million.

The new buys will be formalized Friday as part of the organization's final round of media investments.

The decision comes amid a flurry of concern in GOP ranks that Walker is underfunded and at risk of losing.

The RGA, chaired by Gov. Christie (R-N.J.), has been under pressure in recent days to do more to help Walker, a tea party favorite who rocketed to political stardom after he curbed bargaining rights for most public workers in his state.

The Weekly Standard reported Thursday that there were brewing suspicions on the right that Christie, as RGA chairman, has been “undercutting” Walker, his potential rival for the 2016 Republican presidential nomination.

With his gubernatorial record and presidential aspirations on the line, Walker has also expressed his desire for more money to be dispatched to the state. In an interview Sunday, he said he might require an infusion of cash from the RGA to stay competitive.

Wisconsin Gov. Scott Walker (R) says in this ad that he is "pro-life," but he supports a bill that leaves the final decision for a woman to have an abortion to her and her doctor. (Scott Walker via YouTube)

“Hopefully that comes through,” Walker said. “We are always looking for more help. Our main help has to be the RGA.”

On the campaign trail over the weekend, he underscored his skittishness over financing when he twice cited an Associated Press report from last week that said the RGA and its affiliated groups were being outspent on Wisconsin television by Burke, the Democratic Governors Association and its allies, $6.6 million to $6.1 million.

According to the two officials, the RGA, which has so far spent $5.8 million in Wisconsin, will spend a total of $8 million in Wisconsin by the campaign’s end, counting the supplementary $1 million in ads as well as more than $1 million set aside for grassroots organizing and get-out-the vote efforts.

During Walker’s recall election in 2012, the RGA spent $8.9 million. During Christie’s tenure as chairman, it has raised $90 million.

A Marquette Law School survey released last week showed 47 percent of likely voters supporting each candidate, erasing a five-point Walker lead in the previous Marquette poll. Independents in particular appear to be breaking toward Burke. A New York Times-CBS News poll from last month showed a similarly tight margin.

President Obama, eager to pick off star GOP governors in an otherwise difficult year, plans to visit Milwaukee to rally voters. Former president Bill Clinton will appear Friday with Burke. Both men won Wisconsin twice in their presidential campaigns.

“Rallies and tailgates are wonderful, but in the end we need people on the doors,” Walker said Sunday as he spoke to dozens of Republicans gathered around him in a circle during a Green Bay Packers game-watching party. “I need you to reach out to people you have never talked to about politics before — that’s how close this election is.”