The receiver for Pike River Coal doesn't expect to sign a sale agreement before Christmas as negotiations with international parties interested in the sealed coalmine continue.

"There are a number of international parties that are interested in the mine but they each have their own internal processes to follow which will take longer than we had initially hoped," said receiver John Fisk of PricewaterhouseCoopers.

As part of the sale, the receiver expected to establish a trust that would help oversee efforts to reopen the mine and recover any remains of the 29 miners who died in the blasts in November last year.