The Supreme Court has reserved its decision on whether the Government's sale of power company shares will affect Maori water rights.
The Maori Council and a group of Waikato Maori trusts are appealing against a High Court ruling that there is no connection between the sale of shares in Mighty River Power and the need to address Maori claims to water.
The Government plans to sell up to 49% of the state-owned hydro generator this year if the court ruling is in its favour.
The argument for the recognition of Maori interests in freshwater has also been before the Waitangi Tribunal.
Crown lawyer David Goddard told the Supreme Court on Friday afternoon there was a pressing need for the issue to be determined and there would be prejudice to the Crown if no decision is made before 18 February this year.
However, the Chief Justice said while the court understands the time restraints the Crown is operating under, it could give no indication of how long it might take to deliver a judgement.
The Crown told the court that legislation relating to the sale of power company shares includes provisions for protecting Maori interests.
On Thursday, Maori Council lawyer Colin Carruthers, QC, told the court if the Crown owned 100% of a state enterprise it would be in a better position to address those rights than if it had to take account of the wishes of minority private shareholders.
However, the Crown said the proposed sale regime was largely accepted by the Waitangi Tribunal and that must have some bearing on whether the Crown was taking reasonable steps to deal with the issues.
In closing comments on Friday, Mr Carruthers said that in 1840 his clients had full, exclusive and undisturbed possession of water, and the Crown was obliged to protect that.