BRASILIA, Feb 1 (Reuters) - Brazil's National Monetary Council, the country's highest economic body, announced on Thursday tightened regulations for the issuance of private debt securities linked to financing in the real estate and agribusiness sectors.

These financial instruments, including the so-called CRAs, CRIs, LCAs, LCIs, and LIGs, provide income tax exemptions for investors and have experienced significant growth in Brazil over the past few years.

The changes encompass stricter rules for eligible underlying assets in issuances and will apply exclusively to new operations, said the finance ministry and the central bank in a joint statement, adding that the adjustments "aim to enhance the efficiency of public policy in supporting" the sectors.

They added that the alterations seek to ensure that the "aforementioned instruments are backed by operations consistent with the purposes that justified their creation and contributing to a more robust credit market." (Reporting by Marcela Ayres Editing by Chris Reese and David Gregorio)