By Wisam Mohammed
It will be Maliki's second visit to Tehran after he travelled to Iran in August last year and Iranian President Mahmoud Ahmadinejad made a visit to Baghdad in March.
Government officials would not confirm the date of the visit, but local media in Iraq and Iran said it would be on Saturday.
Maliki's government treads a fine line in its relations with Iran, accused by the United States of supporting Shi'ite militias in Iraq while at the same time seeking support from its neighbour.
"Part of the talks will discuss the subject of the evidence of Iranian intervention in Iraq. We will also talk about the entire relationship with Iran," government spokesman Ali al-Dabbagh told Reuters. "All the issues will be on the table."
Dabbagh would not say which ministers would travel with Maliki but described it as "a political/security delegation".
Iraq's Addustour newspaper said Maliki would be accompanied by Oil Minister Hussain al-Shahristani, Electricity Minister Karim Waheed and Foreign Minister Hoshiyar Zebari.
The report said Maliki would ask for Iranian help with electricity, which is in short supply in Iraq.
Ties between Iran and Iraq have improved since Sunni Arab strongman Saddam Hussein, who led Iraq into an eight-year war against Iran in the 1980s, was ousted in the 2003 U.S.-led invasion and a Shi'ite-led government came to power in Baghdad.
But relations are dogged by repeated accusations from Washington and Baghdad that Tehran is fomenting violence in Iraq by backing Shi'ite militias. Tehran denies meddling in Iraq and blames the violence on the presence of U.S. forces.
Dabbagh said last month Maliki had ordered the formation of a committee to compile evidence of Iranian "interference" in Iraq that would then be presented to Tehran. It is not clear if that evidence will be handed over this week.
A delegation from Iraq's ruling Shi'ite alliance went to Tehran at the start of May to show Iranian officials evidence of the Islamic Republic's backing for Shi'ite militias in Iraq.
Washington accuses Iran of funding, arming and training Shi'ite militias to attack U.S.-led troops and Iraqi government forces, despite its public commitment to stabilising Iraq.
Dabbagh said last month that Iranian missiles had been found in the southern city of Basra during a recent crackdown by government forces on militias there.
The Iraqis have repeatedly said they do not want their territory to become a battleground for a proxy war between the United States and Iran, which are also at loggerheads over Iran's nuclear ambitions.
Iran's foreign minister, Manouchehr Mottaki, told a conference on Iraq in Sweden last week that Tehran was keen to play a major role in rebuilding Iraq and lambasted the United States and its allies for "mistaken policies" in its neighbour. (Writing by Adrian Croft; Editing by Sami Aboudi)
