Mexico's $49 billion, 14-year debt restructuring --

hailed last summer as the beginning of the second phase of the Latin American debt crisis -- finally was sent to its 500 bank lenders over the weekend, seven months after the deal was negotiated

The complicated package -- which covers more than half of Mexico's total foreign debts -- treats Mexico's debt burden as a long-term problem that can best be solved if repayment is stretched over a long period of time -- rather than renegotiated every year.

The Mexican package was used as a model by Venezuela and its bank negotiators when they reached a tentative agreement last September.

Brazil and its bank lenders were near agreement on a long-term debt package, but the talks were put on hold last month because Brazil has been cut off by the International Monetary Fund. The fund, the international financial rescue agency, took the action because Brazil has consistently exceeded inflation and money growth targets it agreed to reach in its pacts with the IMF. Brazil and the IMF are negotiating a new program now.

Mexico, which is in the last year of a three-year IMF program, also has failed to meet some of the IMF targets -- principally on inflation reduction and federal spending -- but Mexican Finance Minister Jesus Silva Herzog told bank lenders that Mexico and the IMF are near agreement for 1985. He said he expected a tentative pact to be initialed within a matter of days.

He said the international agency's executive board is expected to approve Mexico's 1985 program in April. Banking sources said that Mexico's difficulties with the IMF are so minor that the banks have scheduled signing the $49 billion, multiyear bank package for March 29, before the IMF is expected to formally approve the 1985 program.

Unlike Brazil, where money growth and inflation have worsened in the last year -- and where a civilian government will replaced the military regime Friday -- Mexico continued to reduce inflation and spending, although not as fast as it agreed to do. In recent months, Mexico has accelerated the pace at which it devalues the peso and has made further budget cuts.

With the exception of Venezuela, which did not need to borrow new money, major debtor countries have followed economic policies acceptable to the IMF in return for receiving loans from the international agency. The banks have required an IMF imprimatur on debtor country economic programs before they will make new loans.

The bank agreement that went out over the weekend recognizes that after 1985, the IMF-Mexican agreement will expire. Mexico and the banks have agreed that the fund will continue to monitor Mexico's policies and that Mexico will follow policies recommended by the IMF.

Banking sources said that the Mexican loan package was more complicated than envisioned last summer and that it took seven months to work out all the required documentation. Banking sources said the most difficult part of the package to nail down in legal language was a provision that permits banks from outside the United States to switch some portion of their Mexican loans from dollars to other currencies.