Police in Brazil have issued an arrest warrant in connection with the death of Cecilia Haddad in April.

The body of the 38-year-old businesswoman was found in Sydney's Lane Cove River on April 29.

Homicide police in Rio de Janeiro have issued a warrant for the arrest of 40-year-old Mario Marcelo Santoro, her former boyfriend.

He left for Brazil the same day her body was discovered.

Several weeks ago NSW police issued an arrest warrant for Mr Santoro, who was the prime suspect in the ongoing murder investigation.

The body of Ms Haddad was found in Lane Cove River in Sydney's north just a day after friends reported her missing in April.

Suspicions were raised immediately as Ms Haddad was found fully clothed, with weights inside each pocket of her cargo pants.