Mexico will seek $6 billion in new loans from foreign lenders this year, $2 billion more than it had planned to borrow before oil prices crashed, the Finance Ministry said tonight.

Tonight's announcement marked Mexico's first public disclosure of its 1986 foreign credit request since falling oil prices forced it to scrap its original borrowing plans for the year, which called for new commercial loans of $2.5 billion and $1.6 billion in multilateral and government loans.

Finance Minister Jesus Silva-Herzog and Public Credit Director Angel Gurria plan to travel to Washington Wednesday to discuss the borrowing request with U.S. officials, a ministry official said. The Mexican debt negotiators also have scheduled a meeting Friday with private bankers in New York, he said.

Issued following a meeting between Silva-Herzog and President Miguel de la Madrid, tonight's statement said Silva-Herzog's visit to Washington last week laid the groundwork for "what could become a financial and economic package that would resolve the difficulties of 1986 and offer a basis for a broader-reaching negotiation dealing with the total problem of Mexico's foreign debt."

Denying reports that Mexico will need as much as $10 billion in additional credits to compensate for oil revenue losses this year, the Finance Ministry tonight issued a newly revised version of the country's 1986 balance-of-payments outlook that projects additional nonoil export earnings of $500 million and $1.5 billion less in import expenditures than originally had been estimated.

Declining dollar interest rates will save Mexico another $800 million in hard currency this year, the Finance Ministry now calculates. The ministry statement said Mexico will forgo plans to add another $1.2 billion this year to its foreign reserves, estimated unofficially at about $5 billion.