Hobhouse said she had had a huge amount of solidarity from "very worried" MPs.
Foreign Secretary David Lammy has promised to "urgently" raise the issue with authorities in Hong Kong and Beijing and "demand an explanation".
He added it would be "unacceptable for an MP to be denied entry for simply expressing their views as a parliamentarian".
Lib Dem leader Sir Ed Davey has called for Lammy to summon the Chinese ambassador, adding the Chinese government cannot be allowed to "undermine our democracy by intimidating our parliamentarians."
"I want some answers," Hobhouse said, calling for Lammy to "reassure parliamentarians that this is not the way the Chinese communist party can treat [them]".
It comes a week after two Labour MPs were denied entry to Israel while on a trip to visit the occupied West Bank.
"It is very chilling that authoritarian countries can treat us in this way," said Hobhouse, adding the "diplomatic understanding" in which we allow politicians into each other's countries seemed to be "collapsing".
She has ruled out approaching the Chinese embassy for permission to enter Hong Kong, saying they will see their relatives elsewhere.