Police say they are getting more adept at seizing criminals' assets since the Criminal Proceeds Recovery Act came into force in 2009.
The total value of assets seized since then is $39.4 million; between 2012 and 2013 alone the figure more than doubled.
The national manager of the police's financial crime group says assets forfeited in 2012 were worth $7.5 million dollars, but that jumped to $16.6 million last year.
Detective Superintendent Peter Devoy said the bulk of the money seized, $23.8 million, follows prosecutions to do with methamphetamine.
Mr Devoy said some early cases are only being resolved now and that has contributed to the increase in seized assets.
"We currently have about $151 million of assets on restraint and we're closing in on $40 million worth of forfeitures."
Items include a helicopter, boats, farms and 45 houses. Money from a Criminal Proceeds Fund is then bid for by five agencies including the Ministry of Health, Customs and police.
Mr Devoy said as police understanding and use of the legislation increases, they are using it more proactively.