A Māori activist who has been campaigning for years to have Lake Horowhenua cleaned up has padlocked the gates to keep the public out.
Former accountant Phil Taueki, who has been been occupying land beside the lake for 15 years, has waged a long-running battle with Horowhenua District Council over the lake, which is managed by a Crown-appointed board.
His supporter, former district councillor Anne Hunt, said Mr Taueki had successfully defended 36 charges - including trespass - since 2008.
Locking the gates was "a last resort" after the courts refused to uphold the rights of the traditional owners, she said.
Manawatū iwi Muaūpoko was issued a certificate of title for the lake in 1899 but the courts have left it in control of the domain board.
"So in other words, the Māori owners of this lake have less rights than the public on their own property," Mrs Hunt said.
"We've had enough."
Mr Taueki knew that by locking the gates, he was likely to be facing more trouble with the law, she said.
In a written statement, Mr Taueki said the judge's edict that the Māori owners were not to interfere with the rights of the public using the lake was issued "despite Crown Law's failure to produce the agreement they claim modified the rights of the Māori owners".
"Obviously Crown Law could not do so, because no such agreement exists.
"It is now 114 years since Parliament had the audacity to pass a law letting the public use Lake Horowhenua free of charge, and placing control in the hands of a domain board appointed by the Crown."
Horowhenua District Council has yet to respond to questions by RNZ, but said it would issue a statement shortly.
Mrs Hunt said following his second acquittal on the same charge of trespass, Mr Taueki had sought more than $42,000 in legal costs but was turned down.
Mr Taueki is still awaiting trial three more offences (two counts of threatening to kill and one of intimidation) relating to an incident outside the Levin Court building in May 2008 following a Māori Land Court hearing.