(Adds opposition reaction, survey of support for the move)

LIMA, May 29 (Reuters) - Peru's president on Wednesday threatened to dissolve Congress unless his anti-graft proposals are passed, raising the stakes in a power struggle with the opposition that could usher in a new period of political turmoil in one of Latin America's most stable economies.

Invoking a constitutional measure that would authorize him to call new legislative elections if his proposed reforms are not passed, President Martin Vizcarra told Peruvians in a televised address that the fight against corruption was the centerpiece of his administration and accused lawmakers of trying to obstruct it.

"Our firm decision to correct and change the political and justice system affects powerful interests that are protected by unscrupulous politicians," Vizcarra said in a 10-minute message, flanked by his cabinet and regional governors.

"We'll take this struggle to the final consequences, because that's what Peru deserves," he added.

The move triggered immediate cries of "coup" from allies of opposition lawmakers and could stir some debate over its legality, potentially distracting the government from efforts to mediate disputes over mining and oil operations and pass a labor reform package.

Opposition lawmaker Luz Salgado said that lawmakers would evaluate Vizcarra's request for a vote of confidence over his reforms after returning from their scheduled visits with constituents this week.

"We lament the adjectives and name-calling he has used against Congress," Salgado told journalists.

Vizcarra is betting that most Peruvians support him and his legislation following back-to-back graft scandals that have discredited major political parties and institutions in Peru in recent years. A recent poll published in local daily La Republica found that 55 percent of Peruvians wanted him to turn the dispute with Congress into a vote of confidence.

A business-friendly former vice president, Vizcarra took office a little over a year ago after his predecessor resigned in disgrace - one of several politicians entangled in a bribery probe involving Brazilian builder Odebrecht.

Vizcarra's proposals include measures aimed at cleaning up campaign financing, strengthening political parties and ending parliamentary immunity from prosecution.

But his political reform package has languished in commission and the opposition has shelved or voted down other proposals. One congressman who is the target of a criminal probe recently proposed penalties for prosecutors who leak information to the press.