Waitakere City Mayor Bob Harvey says it is not a good look for the region's mayors to be scrapping publicly and they must present a unified voice.
A meeting of the mayors, the head of the regional council and the Local Government Minister is planned for Thursday to discuss the Government's supercity plans.
North Shore Mayor Andrew Williams says Auckland City Mayor John Banks sent him a text message by mistake which he says called him a lunatic.
Mr Harvey says squabbling is a bad look and mayors should stop sending such messages and emails - even if they are angry.
He says there is only a short opportunity, which the mayors need to seize, before the Government has its own way with its plans.