MEXICO CITY, Jan 21 (Reuters) - Mexico's president urged the International Monetary Fund (IMF) on Friday to treat Argentina "fairly" and recognize that the Washington-based lender's own mistakes have contributed to the lingering debt crisis faced by the South American nation.

Mexican President Andres Manuel Lopez Obrador told reporters at a regular news conference that IMF polices should not exacerbate Argentine poverty or otherwise undermine its current government, a key regional ally of his.

"They should treat Argentina fairly, and the International Monetary Fund should accept its responsibility in Argentina's excessive debt," said Lopez Obrador, who raised the subject without being asked about it.

Argentina is attempting to strike a deal with the international lender before the end of March to push back payments on its outstanding $40 billion loan it says it cannot make. Some $18 billion come due this year.

The two sides have been at an impasse over the speed at which Argentina should reduce its fiscal deficit, with the government arguing it needs to maintain spending to support a fragile economic revival.

The country's influential vice president this week lashed out at what she described as debt payments to the IMF last year that she said had cost more than spending on COVID-19.

The current IMF loan deal was struck in 2018 during the previous administration of conservative President Mauricio Macri.

"Honestly, ethically, why not recognize that they made the mistake of giving loans to the previous government beyond what was reasonable?" asked Lopez Obrador, claiming the IMF had been trying to boost the Macri administration by granting the loans.

The Mexican leader, who has warmly embraced fellow leftist Argentine President Alberto Fernandez, added that he viewed conditions sought by the IMF as "totally unfair." (Reporting by David Alire Garcia Additional reporting by Adam Jourdan in Buenos Aires; Editing by Sandra Maler)