Overall pokie machine numbers in Wairarapa have decreased by 21.6 per cent since 2011. In the last quarter of 2015, gaming proceeds in Wairarapa were $1.5 million, compared with $1.9 million during the same period in 2011.
Salvation Army Oasis addiction services public health worker Anoop Gopalakrishnan said the sinking lid policy had "done wonders" for Masterton, where pokie machine numbers fell from 107 in 2012 to 78 by December 2015.
"The results are there to show it is a good thing," he said.
"The biggest reduction has happened in Masterton and we are extremely pleased with this."
The organisation, which has the contract to provide free screening and counselling across the Wairarapa from its office in Masterton, was satisfied the policy was effective in reducing the harm of gambling, Mr Gopalakrishnan said.
As the Salvation Army had only taken over the contract mid-last year, it was too soon to say if there was a similar decrease in the number of clients seeking help, he said.
Carterton councillor Elaine Brazendale, who was part of the combined councils' governance group responsible for reviewing the gambling policy, said the numbers showed the sinking lid policy was working.
"It's the whole benefit of having the policy and looking at the reality of what's happening in the community."
It was a case of balancing people's right to choose how they spent their time while minimising the harm caused by gambling, said Mrs Brazendale.
"We all choose our own recreational activities but when it causes harm to others then it becomes an issue, and we know that when you gamble away your money it has an effect on other family members."