Two men wanted for firearms and drugs offences in the United States have been arrested in Sydney.

The men, aged 31 and 44, were arrested by NSW police following requests from US authorities for their provisional arrest pending extradition.

The arrests follow an investigation into an alleged illegal gun supply route between Nashville in Tennessee, and Sydney.

NSW police and Australian Customs and Border Protection Service have been working with the US Bureau of Alcohol, Tobacco and Firearms (ATF) and the United States Drug Enforcement Administration since last year.

In October 2012, officers from the NSW police firearms and organised crime squad and Australian customs were present during raids by the ATF in Nashville which resulted in a number of arrests.

The multi-agency investigation is ongoing.