There are claims that the Marshall Islands government has acted illegally in signing the new Compact of Free Association with the United States.
Leaders from Kwajalein atoll, where the U.S. military has its base, say the new compact is unacceptable and under the terms of their land lease agreement, the Marshall islands government must seek landowners' written approval.
The compact, among other things, extends the lease of Kwajalein from 2016 to 2086 and parliament is expected to debate and ratify it this week.
Tony de Brum, of the Kwajalein Negotiations commission, says they will take legal action if necessary.
"We are presently studying and our lawyers are carefully examining the terms of the current military use and operating rights agreement signed by our government and the United States. It may very well be that this agreement is in breach of the current land use agreement in which case we will serve notice."
Mr de Brum says the Kwajalein landowners want a trust fund set up with 20 million U.S. dollars and on an annual basis, 3.5 million dollars to go into an environmental fund and rental of 19.1 million dollars.
The U.S. government offered the landowners 15 million dollars annually.
The opposition to the Compact has been widespread with a demonstration held outside parliament this week to protest the provisions within it.