The upper house of parliament or Senate on Tuesday evening delayed voting on plans to introduce a prostitution register and to require clients to make sure sex workers are registered before they use their services.

Justice minister Ivo Opstelten told senators he is prepared to remove the client check, which is aimed at making sure prostitutes have not been forced into the sex trade.

Senators said they want more time to assess the proposals and gather extra information before deciding on the legislation, which has already been approved in the lower house.