The two students, aged 19 and 20, have been working as volunteers for a charity. They have not been named.
They were seized on Tuesday evening outside their apartment in the Ahodwo district and bundled into a car, police said.
Kidnappings in Ghana have been extremely rare until recently, correspondents say.
However, there have been several over the past few months usually involving ransom demands.
Police say the two women are volunteers with Youth Challenge International, a Toronto-based international development organisation.
“Security agencies are working closely together to get them rescued, and the perpetrators arrested,” said David Eklu, Assistant Commissioner of Police.
Global Affairs Canada confirmed the abductions and said Canadian officials were working with authorities in Ghana and were in touch with the families of the two women.
Ghana’s President Addo Dankwa Akufo-Addo has vowed to take a tougher line on kidnappers after a spate on abductions in the country.
In April an Indian man was seized in Kumasi by an armed gang demanding a ransom. He was later rescued in a police raid.
An Estonian diplomat was also kidnapped in April in the capital Accra and again rescued in a police raid, Ghanaweb reported.
Meanwhile, police are still searching for three women kidnapped in December in the southern city of Takoradi.
Two Canadians were kidnapped earlier this year in the west African state of Burkina Faso. One was later found dead and the other, a woman, is still missing.