Israel's foreign ministry said on Twitter on Sunday that three Iraqi delegations visited Israel in 2018, and details were also later released by media.

Baghdad does not recognise Israel, and is technically in a state of war with it.

First deputy speaker of parliament Hassan Karim al-Kaabi called in a statement for "an investigation... to identify those who went to the occupied territory, particularly if they are lawmakers".

"To go to the occupied territory is a red line and an extremely sensitive issue for all Muslims", the statement said.

Kaabi is close to Shiite leader Moqtada Sadr, whose bloc won the largest number of seats in Iraq's legislative election last year.

Israel's foreign ministry said on Twitter that the 15 Iraqi visitors were "influential Shiite and Sunni personalities in the country", but did not give names.

The ministry said the Iraqi travellers had visited "Israeli officials and universities", as well as the Holocaust memorial in Jerusalem.

A spokesman for the memorial told AFP that "a group of 10 Iraqis" had "undertaken a guided tour in late December".

He said he was not able to give details on the identity and roles of the Iraqis.

Private Israeli TV station Hadashot, which described the Iraqis as "local leaders", said Sunday that they had stressed they were not taking part in an official visit and that secrecy was paramount.

A significant Iraqi Jewish community lives in Israel and regularly calls for a normalisation of ties between Baghdad and the Jewish state.

But the question remains sensitive and Israel's support for an independence referendum in Iraqi Kurdistan in late 2017 provoked Iraqi officials' ire.

Israel was the only country to back the vote, which Baghdad deemed illegal.

In 2017, a former Miss Iraq sparked a storm when she took a selfie with Miss Israel.