Michael Kovrig, a former diplomat, and Michael Spavor, a China-based businessman, were detained last December for reasons of "national security".
The case triggered a row between Beijing and Ottawa.
Canadian daily The Globe and Mail reported Thursday that no formal charges have been leveled against the two.
Canada's Foreign Ministry condemned the detention of its nationals as "arbitrary arrest".
China has accused Kovrig of spying and "stealing state secrets", and Spavo of providing him with intelligence.
