Eighteen months of complex and volatile negotiations boiled down to one of history's most familiar financial dilemmas last night at the Conference on International Economic Cooperation: Take the money and run, or hold out for more?

That, in essence, was the question confronting the 19 developing and oil-producting countries that have been pushing for sweeping reforms in global trade and finance through the conference, more familiarly known as the North-Sruth Dialogue.

The group of 19 and the eight delegations representing the world's major non-Communist industrial nations spent the day behind closed doors negotiating over proposals made yesterday by the industrial countries. The conference is to end Wednesday, even if agreement is not reached.

Instead of what the 19 Third World nations sought - a massive transfer of wealth from the North to the South and a wiping out of an estimated $200 billion in debts owed by less-developed countries - the North American, European and Japanese delegations offered promises of increased aid, selective debt relief and modifications in trade.

Secretary of State Cyprus Vance suggested to the conference yesterday that the new aid increases and other incentives were conditioned on a harmonious ending to the formal North-South talks. He said the United States favors continuing a general dialogue on the issues raised here, in another unspecified forum.

Third world delegates reacted with reserve to Vance's proposals and sought throughout the day's bargaining to get the industrial nations to commit more resources to reducing global poverty and giving exporters of raw materials guaranteed income levels.

"This conference should constitute a turning point in ternational economic relations," Venezuela's Manuel Perez Guerrero, said, speaking for the 19 delegations, which evidently fear that they are being put off again with promises of future aid rather than a substantive deal now.

"We are looking for some fundamental charges and not for some isolated gesture, most of which are not yet clear, aiming at dealing with short-term problems," Perez Guerrero said. While some of the measures outlined yesterday were "positive" they were "isolated" and "far below our expectation's, he said.

Venezuela and Brazil appeared to be leading a hard-line Latin American faction that is suggesting that they prefer to leave Paris with no agreement and a chance to blame the West rather than accept what they see as placebos.

Other leading delegations in the group of 19, including Algeria, Iran, Saudi Arabia, Zaire, India dnd Pakistan, appeared to be seeking areas of compromise.

Among the financial incentives for quick agreement are a special $1 billion fund for the Third World's poorest countries, to which the United would contribute $375 million. Canada offered to wipe out $254 million in debts owed it by Third World nations, and Japan said it would double its present aid program over the next five years.

But the 19 are still pushing for an indexing of raw material prices to consumer goods and for a moratorium on bebts owed to Western governments and banks.

The eight reject these proposals, and are seeking - against Saudi resistance - a special dialogue on energy supplies. Perez Guerrero hinted that a compromise on the energy issue may be in the works.

The delegations split into three working groups today, discussing finance and energy in one body and raw materials and development aid separately. They were to return to work late in the evening after a dinner given by French Foreign Minister Louis de Guiringaud.

Vance spent a good part of the day in bilateral talks rather than participating in the conference. He and Indian Foreign Minister Atal Behari Vajpayee discussed nuclear energy for nearly an hour and a half.

The Secretary of State also met with Nigerian Foreign Minister Joseph Garba and pakistan's Foreign Minister Aziz Ahmed.

(The United States and Pakistan agreed to restore relations to the friendly footing that had existed, before Pakistani Prime Minister Zulfiqar Ali Bhutto accused Washington of backing an opposition campaign to overthrown him, Reuter reported.)