The NDP and the Greens have a deal that would see the New Democrats form a minority government if the Liberals are defeated in the legislature.
Weaver and B.C. Liberal house leader Mike de Jong traded criticisms Thursday, de Jong from outside the Vancouver cabinet offices and Weaver from the B.C. legislature.
"If the Greens and the NDP are purporting to be able to provide a stable government for British Columbians, then they have to do it from within their own resources", he said.
"The practical workability of that agreement is very much in doubt", he said.
Because the NDP-Green alliance has 44 seats and the governing Liberals have 43, Weaver told Postmedia columnist Mike Smyth this week that it's crucial to get a Liberal in the speaker's chair.
"The NDP-Green agreement states that an NDP-Green government would implement an increase in the carbon tax by $5 per tonne per year", the report reads.
"This is nothing more than to work the people of British Columbia into a tizzy about a non-existent crisis".
As to the complaints that government isn't reconvening fast enough, De Jong said the legislature is not meeting any later than it normally does after other May elections.
"Peter Milliken, elected Speaker after five ballots under (former prime minister) Jean Chretien back in 2001, served as the Speaker through successive Conservative minority and majority governments", Weaver said Wednesday.
He noted that two weeks were needed to recount votes for close ridings and confirm which party formed government.
Horgan suggested the person who becomes Speaker next week, likely a member of Clark's caucus, should remain in the position following the expected defeat of the Liberal government in a confidence vote later this month.
But Weaver said there's no reason why a vote couldn't be held the day after the throne speech is delivered.
"If ever there was an example as to why we need a change now, it's the antics, shenanigans, delay and distraction that have gone on since the election", Weaver said.
The institute says it based its findings on the Greens' pledge to "roll MSP payments into the payroll tax and personal income tax" and the NDP's intent to "replace the lost revenue with increases in other taxes".