A severed human foot has been mailed to the headquarters of Canada's ruling Conservative party, police said.

A box containing the foot was delivered by Canada Post on Tuesday, Ottawa police said in a statement.

Officers were called by someone at the party offices reporting a suspicious package. The first to arrive saw what appeared to be bloodstains on the package and called in a special hazardous material unit.

Police said a coroner later determined that it was a severed human foot in the box.

Police in Montreal investigating a torso found in a rubbish bin were checking on whether there might be a link.

Police were called shortly after a receptionist opened a blood-soaked box.

Officers said the package was addressed to the Conservative Party of Canada and not to a specific person. Prime minister Stephen Harper's office is not located at the party headquarters.

Ottawa police said it was too early to speculate on a link with a severed torso found in a suitcase in Montreal, but authorities in both cities are trying to determine if there might be a connection.

A Conservative parliament member who showed up later at his party's headquarters was horrified by the discovery.

"It's just awful," said Brad Trost, who learned about the incident from TV. He said it was probably someone's "sick idea".

"I don't think any of us are thinking this necessarily has anything to with politics," he said.

As the investigation developed, Ottawa police said they had intercepted a second suspicious package containing another human body part.

Police released no other details about the second find, but said the major crime section continues to investigate.