In a response to a question on the issue by MP David Simpson, he said: "We believe that freedom of religion or belief is a fundamental human right.
"I remain concerned by the restrictions placed on Christianity in China.
"We are aware of reports of the closure or demolition of churches, the removal of crosses from buildings, and that individuals are being harassed or detained for their beliefs.
His comments come just weeks after Mr Cameron hosted Chinese President Xi Jinping on his state visit.
He said during the visit he was able to make clear the "importance that the UK attaches to human rights as part of our wider relationship with China".