He said the iwi would not rule out taking a case to the Supreme Court.
"That's always a consideration but we need to evaluate things once we've gone through all the findings carefully."
The trusts are seeking to buy two of the Crafar farms at Benneydale, south of Te Kuiti, which they say are of historical and cultural importance to them.
Mr Peni said the trusts would also seek to restart stalled negotiations with Shanghai Pengxin to buy the farms. But a spokesman for Sir Michael said the investment banker and other members of his group accepted the court's decision. "From our point of view the decision is pretty emphatic."
In a statement, Sir Michael said he felt "disenfranchised" as well as disappointed by the decision.
"We are all disappointed - especially our two iwi members - to see this significant parcel of highly productive dairy land pass out of New Zealand ownership."
Labour leader David Shearer yesterday repeated his party's call for tougher standards for foreign investors to buy productive land.
He said Mr Williamson's and Dr Coleman's decision to approve Shanghai Pengxin's application was "just another example of National kowtowing to foreign investors and neglecting the needs of our rural heartland".