Police in Newfoundland say a total of five suspicious packages were reviewed without incident.
In Nova Scotia, the RCMP said court buildings in Sydney, Yarmouth, Digby, Port Hawkesbury and Truro either had suspicious packages delivered or were intercepted before delivery on Wednesday.
RCMP Staff Sgt. Boyd Merrill says the packages in Newfoundland were reported in Grand Falls-Windsor, Gander, Stephenville, Clarenville and Grand Bank.
The RCMP say none of the packages have so far posed a risk to the public.
In Nova Scotia, the Mounties have assigned their major crimes unit to the case.
"At this time we do not believe these packages put the public at any risk, however we must remain vigilant and take all necessary precautions," Insp. Larry Wilson of the major crimes said in a statement. "We will work closely with each affected police agency, partners and the Nova Scotia Department of Justice to advance this investigation."
The rash of suspicious parcels prompted the Department of Transportation and Works in Newfoundland and Labrador to suspend operations at seven provincial mailrooms. It plans to resume normal operations on Thursday.
Two more packages forced the evacuation of the provincial Supreme Court building in St. John's and the Danny Williams Building, a court complex in Corner Brook.
Three of the packages in Newfoundland have been confirmed by police as originating from the same international address and with similar contents to packages reviewed by the RCMP in Nova Scotia.
But RCMP say they can't confirm any link with similar deliveries in Nova Scotia and Manitoba.
Earlier this week, envelopes were sent to Nova Scotia court buildings in Amherst, Truro, Kentville, Bridgewater and Halifax.
Cape Breton Regional Police say the package in Sydney appears to be similar in nature to those received elsewhere in the country.
They say the envelope was contained in a secure area and no one came into contact with its contents, but the main floor of the court building was evacuated as a precaution.
Packages were received April 8 at Manitoba provincial court buildings in Winnipeg, Brandon, Morden and Minnedosa, all of which tested negative for dangerous substances.
A spokeswoman for the Manitoba provincial court system has said she was told the packages contained reams of paper filled with case law. She said packages, believed to be from China, were also sent to court offices in Portage La Prairie and Thompson.