Prime Minister John Key has signed a Tax Information Exchange agreement with Cook Islands Prime Minister Jim Marurai as part of efforts to clamp down on tax evasion and avoid another wine-box affair.

Revenue Minister Peter Dunne said the Tax Information Exchange Agreement provides for full exchange of information on criminal and civil tax matters between the two countries.

"The agreement will enable the tax authorities of both countries to gain access to information about income and assets that would-be evaders try to hide in the other country," Mr Dunne said.