From the opinion:

The State's contingent interest in the restrained property is of a punitive nature and limited to depriving Mr Dotcom of the fruits of his alleged offending. In contrast, MrDotcom's access to counsel is supported by his rights to natural justice," to be presumed innocent until proven guilty," and to consult and instruct a lawyer and to have adequate time and facilities to prepare a defence." It is generally assumed that the right to access defence counsel includes the right to counsel of the defendant's choice (though exceptions apply to legally-aided persons)

... In this case, there is no evidence that this right has been exercised in an irresponsible manner. Mr Dotcom has been obliged to respond to the proceedings initiated by the United States authorities and there is no evidence that he has unnecessarily prolonged the proceedings or otherwise acted irresponsibly in relation to his defence... Where legislation can be interpreted consistently with rights guaranteed by the New Zealaod Bill of Rights Act 1990, that interpretation should be preferred.

...I conclude that Mr Dotcom should be allowed access to his restrained properly to pay legal expenses relating to his defence on a solicitor and client basis, provided that the costs are not wasteful or dishonestly incurred and claimed.

As to the amount of legal fees and whether they are excessive, the Court says it should not be the one to make that determination.

I consider an appropriate solution is to appoint an independent Queen's Counsel to review the fees and disbursements charged to Mr Dotcom and to report the result of his or her assessment to the Official Assignee, Mr Dotcom and the Commissioner.

The Judge said Kim Dotcom's funds can't be used to pay legal fees for his co-defendants. His wife can probably get her legal fees covered if she makes an application.

As to future legal fees needed by Dotcom,

I therefore order that $lM [$1 million] be set aside as a fund for Mr Dotcom's future legal expenses. Payment of legal expenses from this fund will be subject to the same supervisory jurisdiction as current legal expenses. Any future legal expenses claimed by Mr Dotcom's legal advisers must be reviewed by the supervising Queen's Counsel and paid by the Official Assignee, in accordance with the criteria and process set out above. Any part of the fund for future legal expenses which is unexpended shall be held by the Official Assignee on interest bearing deposit.

Ars Technica article on the decision is here.