A caucus is a group of MLAs who, often on the basis of their political party, meet regularly and privately to discuss policy, strategy, and tactics. Private Members, who are usually bound by party discipline to not express any disagreement with their party's position in public, are able to use private caucus meetings to speak freely with their colleagues.
Cabinet often uses the government caucus as a sounding board for proposed legislation before it is brought before the Legislative Assembly.
An opposition caucus will meet to discuss government activity and public policy. The primary purpose of an opposition caucus is to develop parliamentary strategies and tactics to hold the government to account and to develop alternatives to government policies.