The World Bank yesterday approved a "special action program," designed to speed up disbursement of $2 billion in planned loans over the next 24 months. These will go to developing nations to help relieve accumulated economic pressures, including the burdens of huge international debts, administration sources said last night.

Most of the faster action will be directed to upper- and middle-income developing nations that borrow money at regular rates from the World Bank. But some of the acceleration will also help so-called "blend" nations, those that get a mixture of regular bank loans as well as subsidized money from the International Development Agency, the bank's soft-loan affiliate.

The action was taken unanimously by the executive directors after a day-long meeting in which all bank lending and borrowing programs were reviewed. An administration official said after the meeting that the United States "looks with favor" on speeding up bank lending, "provided it is limited and temporary."

A detailed announcement of the steps the bank plans to take to increase its lending activities--and to what extent it will have to increase its borrowing--will be made this morning at a press conference conducted by World Bank Vice President Ernest Stern.

One way of speeding up the outflow of money that was discussed at yesterday's meeting is to boost loans for so-called "structural" purposes--temporary financial difficulties, for example, as opposed to loans for construction projects. Disbursements on "structural" loans can be moved up fairly quickly.

A companion proposal to help the poorest of the Third World countries will be taken up by the board at its meeting next month. This contemplates the transfer of a larger-than-normal sum of money from World Bank profits to the account of its subsidized lending arm, the International Development Agency.

But although the shortfall in IDA funds has been caused by Congress' delaying approval of promised funds, the Reagan administration will oppose any unusual transfers of World Bank funds to the IDA.

The bank in recent years has turned over a modest part of its profits on conventional loans to the IDA. For example, it transferred $101 million to IDA out of profits of $610 million in fiscal 1982 and $118 million out of profits of $588 million in the prior year.

Actual loans through the IDA soft-loan window are falling below a budgeted level of between $3 billion and $3.5 billion for this year, primarily because a decline in the U.S. share triggers an equal decline from other donor nations.

IDA makes 50-year, interest-free loans, with only a 0.75 percent service charge, to the poorest of the poor countries, those with per capita income of less than $411 in fiscal 1982.