There is no way the Tasman community can avoid the extra cost of ensuring future water security, says Regional Economic Development Minister Shane Jones.
Jones is meeting the Tasman mayor tomorrow to discuss the $102 million Waimea Dam.
There is concern the council is being expected to pay too much to try and cover a $26 million funding gap.
Jones says if they don't accept the Crown's grant and loan offer of around $39 million, they must absorb the entirety of the costs themselves.
"This is not a time for making decisions on the basis of astrological charts. Economic rationality and long term confidence is absolutely needed."