Access being reserved means it is yet undecided by the Court. It can apply in different ways.
For instance here it was reserved as the court felt the parties could work it out themselves.
The question of access was reserved by consent in the Magistrates Courts because the parties believed that they could arrange between themselves all matters of access. (Armstrong and Armstrong  FamCA 57).
In another matter it was reserved, pending the court receiving more information. access were reserved ; a sec. 62A welfare report order was granted; a special fixture in February was ordered; the only procedural order was that not less than seven days before the commencement of the hearing of the application each party was to file and serve any further affidavits sought to be relied upon at the hearing and any amendment to any pleading. ((1987) FLC ¶91-810).
The term is not often used, according to the austlii database the last published case was 1996 for the Family Court.