Officers began digging at two addresses in Broad Street, Swindon on Monday.
Taxi driver Halliwell was jailed for life last year for the 2003 murder of Becky Godden, having already admitted killing Sian O'Callaghan in 2011.
Wiltshire Police said the excavation was related to new intelligence the force had received.
The search was initially expected to last five days.
Det Ch Insp Jeremy Carter said: "Work at the site will pause for the weekend on Friday and we will reconvene to commence searching once again on Monday next week.
"The alleyway which runs alongside these garages and gardens will remain cordoned off during this time and police officers will continue to patrol the vicinity. We aim to keep this disruption to a minimum as much as possible."
He stressed the occupants of the properties have no involvement in the investigation.
Several security staff have been guarding the scene of the search and a black tarpaulin is covering an alleyway by the house where white forensic tents have been erected.
Halliwell was jailed for life in 2012 for the murder of Miss O'Callaghan, 22, and was told he must serve at least 25 years in prison.
He was convicted of murdering Miss Godden, 20, last September and given a whole-life sentence.
A search of the garden of a property where double-killer Christopher Halliwell once lived will continue into next week, police have confirmed.