I know National Party Voters who have complained about at least one Coalition policy. Of course we never voted for the Coalition platform, we voted for the individual parties. The NZ Westminster system has a Loyal Opposition. Complaining about the government’s actions is part of it! Vocalised and expressed Complaints celebrate our democratic freedom.
Also not all National MP’s are part of the government but they are whipped into voting for it in parliament. Sometimes opposition and complaints about government policy come from within a party, which helps form the government.