The Solomon Islands Christian Association says the government is not considering what impact another casino would have on locals.
Its general secretary, the Reverend Eric Takila, says it is opposed to the government granting a third casino licence.
The Papua New Guinea based Constantinou Group wants to build a five star hotel, including a casino, on prime land in Honiara that it acquired from the Government earlier this year.
Rev Takila says having casinos may appeal to some tourists but it perpetuates gambling and other social problems among locals.
"I don't know the rationale behind it but the country is going through a process of rebuilding. We should look at building an economy based on other things, like agriculture and fisheries and not make shortcuts by building casino's."
Reverend Eric Takila of the Solomon Islands Christian Association.