Brazil's Rousseff replaces congressional liaison

* Rousseff's congressional liaison Sergio resigns

* Former Workers' Party senator Salvatti replaces him

* Cabinet switch follows resignation of chief of staff

BRASILIA, June 10 (Reuters) - Brazilian President Dilma Rousseff made the second key change of the week in her cabinet on Friday, her office said, a move aimed at improving strained ties with allies in Congress.

Luiz Sergio, the minister responsible for liaising with Congress, resigned from his post, Rousseff's office said in a statement. This followed complaints from Rousseff's allies that Sergio was ineffective in managing relations with the 10-party ruling coalition.

Rousseff picked fisheries minister Ideli Salvatti of the ruling Workers' Party, or PT, to replace Sergio, while Sergio will assume the job of fisheries minister, the statement said.

Salvatti is a long-time legislator and former coalition leader in the Senate.

Rousseff's influential chief of staff, Antonio Palocci, stepped down on Tuesday over a personal finance scandal, depriving the administration of its most influential minister and a Wall Street favorite. [ID:nN07160555]

A lack of congressional support for Palocci helped hasten his fall. [ID:nN07177307]

Rousseff has focused heavily on technical and administrative matters since being sworn in on Jan. 1, winning plaudits in some quarters for her diligent approach but stirring discontent in Congress over what some see as a detached attitude.

Coalition partners including the centrist PMDB party have complained of being sidelined on major government initiatives and want more say in the decision-making process.

Rousseff met with Vice-President Michel Temer of the PMDB on Thursday night to discuss the situation, according to local media reports.

Analysts say the meeting and the ministerial shuffle are part of a broader effort by Rousseff to improve ties with the PMDB, the largest party in the ruling coalition.

(Reporting by Hugo Bachega; Writing by Raymond Colitt; Editing by Will Dunham)