By Diego Ore and Daniel Wallis
CARACAS (Reuters) - Venezuela's President Nicolas Maduro said on Monday he will ask for decree powers last used by his predecessor Hugo Chavez to ramp up a fight against corruption that has begun to cost him politically with supporters.
Maduro, who served as Chavez's foreign minister and vice president, narrowly won an election four months ago after his socialist mentor died of cancer.
He has struggled with slowing economic growth and rising inflation while also trying to impose control on the diverse coalition he inherited from Chavez. It ranges from military officers to businessmen, leftist ideologues and armed militants.
A new anti-corruption drive that Maduro launched with great fanfare has led to the arrest of some relatively senior officials from state-run businesses and institutions.
But it has suffered from a widespread public perception that "big fish" with political connections have been spared.
In a nationally televised speech, Maduro said he would ask the National Assembly, which is dominated by his supporters, to grant him decree powers to step up his battle to defeat graft.
"I'm going to call a national emergency in the fight against corruption, and I'm going to ask for special powers in order to change the laws," he said. "If I have to change all the laws to confront corruption, I'm going to do it."
To be granted decree powers, Maduro would need the votes of three-fifths of the National Assembly, or 99 deputies. His ruling Socialist Party holds 98 seats, so he would need just one independent lawmaker to back him.
Chavez governed for months using decree powers that he requested from lawmakers in 2010 to push through reconstruction and relief projects after floods left nearly 140,000 homeless.
At the time, critics accused him of exploiting the disaster to sideline the Assembly before the arrival of a raft of opposition legislators elected that year.
Chavez later said he was being demonized around the world for ruling by decree, and at one point said he would give up the powers if the post-flood measures were put in place quickly.
It was unclear what laws Maduro might change by decree, and he gave few details in his speech.
In its latest annual index of perceptions of corruption, global watchdog Transparency International ranked Venezuela as the ninth most corrupt country in the world.
Among the senior officials caught up in Maduro's anti-graft campaign are five who are charged with embezzling $84 million from a China-financed development fund.
But many Venezuelans openly wonder why some individuals widely believed to be corrupt, including heavyweight figures close to the government, have not been brought to justice.
Some "Chavistas" see that as a betrayal of their late hero's memory, so the perception that his administration is soft on corruption has become a challenge for Maduro that rivals violent crime and the economy.
(Writing by Daniel Wallis; Editing by Xavier Briand)