Former lover of murdered Sydney businesswoman Cecilia Haddad to be extradited from Brazil

The Attorney-General will have to persuade Brazilian authorities to extradite a man wanted in Sydney over the murder of businesswoman Cecilia Haddad.

9NEWS confirmed a warrant has been issued for the arrest of Ms Haddad's ex-lover, Mario Marcelo Santoro, who slipped out of Australia around the time her body was discovered.

Santoro was found to have departed Sydney for Rio De Janiero on the same day his 38-year-old former partner, also from Brazil, was found floating in the Lane Cove River in late April.

While there is a warrant for Santoro's arrest, Brazil does not have an extradition treaty with Australia, which is expected to make Attorney-General Christian Porter's role difficult.

But 9NEWS understands that because Santoro is the prime suspect in the murder of a Brazilian national, negotiations for an extradition deal should be made easier.

Santoro spoke to New South Wales detectives in the wake of Ms Haddad's death and was listed as a person of interest. He is yet to be charged.

In May Mr Santoro said he "placed (himself) at the disposal" of police.

“I have nothing to say about this, you will have to speak to my lawyer," he told the Telegraph.

Ms Haddad's death came just weeks after she ended her relationship with Mr Santoro.

The pair had been both romantically and professional involved for ten years before Ms Haddad kicked Mr Santoro out of her Ryde apartment.

The former mining executive is believed to have missed a string of appointments the day before her body was found.

Friends said Ms Haddad "seemed anxious about something" when communicating with them over the phone Saturday morning.

Ms Haddad's red Fiat was found parked at West Ryde train station the following afternoon, around six kilometres from the location where her body was found.

Police said they are pursuing a number of leads but have otherwise declined to comment.