Sen. John Ensign spent $551,000 in legal fees for himself and his aides in the third quarter, the Las Vegas Review-Journal reported Sunday.

The Nevada Republican raised less than $19,000 for his campaign fund during the period and spent about $700,000 overall, leaving about $280,000 in the bank, the newspaper reported, citing a campaign report filed Friday. Ensign is up for re-election in 2012.

“Senator Ensign’s focus has been on his constituents and the many town hall meetings that he has held across the state to hear directly from Nevadans on the issues that matter most to them,” his spokeswoman, Jennifer Cooper, said in an e-mail to the Review-Journal. “Fundraising efforts have taken a back seat up until now, but Senator Ensign has every intention of stepping up his fundraising in the coming year.”

The Senate Ethics Committee and the Justice Department are investigating whether Ensign broke laws or Senate rules in an alleged attempt to cover up an affair with Cynthia Hampton, a campaign staff member married to Doug Hampton, his Washington administrative assistant. Ensign set up a separate legal expense fund this year, and a report from it is due later this fall.

The Senator, who is married, admitted to the affair in June 2009, saying it spanned nine months over 2007 and 2008. The Hamptons no longer work for Ensign.

Some of the third-quarter spending has covered the legal fees of aides who have been contacted for questioning in the investigation. No allegations have been made regarding his staff members.

Payments to a dozen law firms included $25,000 to Covington & Burling LLP, $8,166 to Akin Gump Strauss Hauer & Feld LLP and $10,327 to DLA Piper LLP, according to the report.