A Warwick St property in Mayfield was searched yesterday, with several items of interest seized by police, Senior Sergeant Ciaran Sloan said.
This morning another property was searched in Henderson St, Riversdale, where "samples of forensic value" were seized.
Forensic scientists helped police at both addresses.
Occupants of both properties have been spoken to by police but no arrests were made, Sloan said.
The investigation continues to receive information from the public and investigators are steadily working through inquiries that have been generated from that information, he said.
Boyce was last seen in Renwick on Tuesday, March 19, driving a red Holden Rodeo ute.
Police located her vehicle at the Lake Chalice car park in the Richmond Ranges on Friday, March 22.
They now believe her vehicle, which has been seized for forensic examination, was left in the car park in an effort to mislead the investigation.
Sloan earlier said police have identified a number of other locations of interest in Marlborough as a result of their inquiries.
"Additional resources from the Tasman and Canterbury Police Districts have been deployed to Marlborough to assist with the investigation, which remains a priority for police."
Anyone with information is asked to contact Marlborough Police on 03 578 5279, or Crimestoppers anonymously on 0800 555 111.
