Labour list MP Shane Jones says the Maori claims over fresh-water have a parallel, in the successful Maori fisheries claim that led to the Sealord deal.
But he says to succeed, the claims will need more than a favourable Waitangi Tribunal report.
The Tribunal has granted an urgent hearing of the claims by the Maori Council and 10 hapu, saying Maori rights should be clarified before the Government sells shares in power companies, or reforms freshwater management.
Shane Jones, who was part of the ground-breaking Muriwhenua claim in 1986, says fisheries reforms at that time created new property rights in the form of fishing quota and Maori claiming customary rights negotiated a share of that with the Government.
But he says he doubts the present Government would do the same with water, unless it had to.
Mr Jones says the claim could also fall prey to internal Maori politics, with argument about whether water rights attach to tribes - or whether water is something all Maori have interests in.