His ruling on Thursday followed a complaint about a National video featuring Labour MP Deborah Russell making a speech about wellbeing, before trailing off onto Greek philosophy.
"While there has been some discussion about what constitutes a 'political advertisement', it is clear to me that videos that support one party or aim to reduce support for another party are the sorts of items covered by [Parliament's rules]," the Speaker told the House.
In past, both Labour and National have run video that would have broken the rule, but Mallard's ruling only applied to ads made in 2019.
Calling the ruling a "chilling move designed to stop freedom of expression", every member of the National Party on Friday instead reposted the video of Russell.
"He has pushed the matter to a process, which effectively gags us for a significant period of time," Opposition leader Simon Bridges said.
National declined to comment on Monday.
Public submissions on the rules will be open until October 16.