BAGHDAD (Reuters) - Iraq's main Shi'ite groups on Sunday voiced support for Prime Minister Haider al-Abadi's plan to overhaul the government and combat corruption, state TV said.

The broadcaster cited a statement issued by the National Alliance, a loose gathering of Shi'ite groups that controls the majority of seats in parliament, after a meeting with Abadi in the Shiite holy city of Kerbala, south of Baghdad. The other blocs in parliament mainly represent the Sunni and Kurdish communities. Abadi, 19 months into his four-year term, said in February that he wanted to replace politically-appointed ministers with technocrats in a bid to weaken the current system which distributes positions along ethnic and sectarian lines, creating patronage networks blamed for breeding corruption.

Abadi's move came after criticism from the nation's highest Shi'ite cleric, Grand Ayatollah Ali al-Sistani, that his government has done little to combat graft. "The National Alliance affirms its position of support of the reforms and ministerial change that the Prime Minister has called for," the statement read on state TV said.

The Shi'ite meeting in Kerbala was attended by Moqtada al-Sadr, the powerful cleric who called on Friday for the government to be overthrown if it failed to act against corruption, according to state TV.

Sadr, whose opinion holds sway over tens of thousands of people, including fighters who took on U.S. troops in 2006-07, had threatened to break into the heavily-fortified Green Zone that houses main government buildings, the parliament and foreign embassies.Representatives of Abadi's ruling Dawa party and Ammar al-Hakim, the leader of the Islamic Supreme Council of Iraq ‎were also present at the Kerbala meeting, according to state TV.

(Reporting by Maher Chmaytelli; Editing by Andrew Bolton)