MEXICO CITY: Ratings agency Moody's Investor Services said on Wednesday that the Mexican government should significantly increase financial support for national oil company Pemex, a day after it presented its business plan that underwhelmed the market.

Pemex is the world's most heavily indebted oil company and on the verge of losing its investment grade rating after Fitch downgraded it to speculative grade, or junk status.

A second such downgrade from one of the three large ratings agencies would trigger forced selling of Pemex bonds worth billions of dollars.