The final tick for a parliamentary select committee inquiry into the price of milk is expected to be given at the National Party caucus today.
Labour and the Greens have been pushing for such a probe after the Commerce Commission last week decided not to hold a formal investigation into milk prices.
Cabinet yesterday agreed to support an inquiry, and National would make the final decision in its meeting this morning.
Prime Minister John Key said he expected the caucus to take the same view as Cabinet.
Mr Key said the Government's initial reluctance around a select committee inquiry was due to concerns it would cut across work that was already being done on the issue.