Jordan and the Palestine Liberation Organization are nearing agreement on arrangements which may allow King Hussein to enter into Middle East peace negotiations with Israel, according to Jordanian government officials and aides to PLO chairman Yasser Arafat.
But it is so far uncertain to what extent - if at all - the arrangements would include the Reagan Mideast peace proposals.
Mr. Arafat interrupted a six-day visit to Jordan Tues-day after having held almost 10 hours of talks with King Hussein for what PLO officials described as an ''urgent, very important and short Arab tour.''
PLO officials confirm that a last-minute snag ''on our side'' prevented the publication of a four-page joint Palestinian-Jordanian communique and made Mr. Ara-fat's sudden Arab tour necessary. Refusing to be more specific, an aide to Mr. Ara-fat said Monday: ''Something happened here tonight but we hope to publish the communique when the chairman (Mr. Arafat) returns to Amman later this week.''
Western diplomats cautioned, however, that the two leaders may choose to keep their agreement secret.
The PLO chief was quoted upon his arrival in Kuwait as saying that ''King Hussein and I are agreed on what is good for both sides.'' Mr. Arafat was said to have denied reports that Syrian-backed hard-line Palestinian opposition was blocking an accord on Jordan's role in future Middle East peace negotiations.
Jordanian government officials urged reporters Tuesday to stay in Amman despite Mr. Arafat's departure. ''A dramatic development is imminent,'' one official said.
Mr. Arafat is expected to continue from Kuwait to Saudi Arabia before returning later this week to Amman.
PLO officials say Mr. Arafat will hold several rounds of talks with King Hussein upon his return to the Jordanian capital ''within the next 72 hours.''
Senior aides to the PLO chairman told The Christian Science Monitor that King Hussein and Mr. Arafat ''still have to work out the details on a number of issues.''
These issues are said to include:
* The shape of a proposed confederation between Jordan and any future Palestinian entity.
* The representation of the Palestinians in peace negotiations with Israel.
* The possible moving of PLO offices to Amman.
The question of who should speak on behalf of the Palestinians is perhaps one of the thorniest issues within the PLO.
PLO officials stress that the representation of the Palestinians by the PLO is ''non-negotiable.''
A PLO official suggested, however, that a compromise was possible. ''How you do it is certainly a negotiable item,'' said PLO executive committee member Hanna Nasser.