Collins said she was prevented by the Policing Act and the Cabinet manual from intervening in police operations.
"This is not a matter I can comment on. It is currently with the IPCA and for me to make a statement about that or have any sort of view would in fact actually try to influence the IPCA investigation."
That prompted Labour MPs to shout across the debating chamber that the Government was "stopping old ladies".
Seymour questioned the use of police resources to target "law-abiding people attending a peaceful meeting" in light of figures released yesterday which showed burglary rates had risen.
Collins reiterated that she was not going to "wade into [the IPCA's] investigation".
The IPCA has also received three complaints from the public about the fake police checkpoint.