The Scottish Government has been criticised over talks for "key workers" to protect public services in the coronavirus crisis.
In Scotland, all 32 councils have been given freedom to draw up lists following school closures.
The GMB union suggested the approach is too vague, warning: "This does not look like a coordinated response to us, because it isn’t one."
Deputy First Minister John Swinney had earlier set out three main categories. He confirmed children of workers such as nurses and police will get access to learning and childcare.
The top priority covers those directly responding to the coronavirus response. A second tier covers most emergency services, while a third covers workers whose absence would hurt essential services.
Councils were given six days to reflect the "diverse range of localities".
Announcing his plan on Friday, Swinney said: "Local authorities are best placed to decide on the exact definition based on local needs which will obviously differ in island and rural communities to that in our cities."
Senior figures in the GMB said government ministers had "no engagement" in discussions with them and the Convention of Scottish Local Authorities (Cosla), representing councils.
The union wants a nationally agreed list of key workers, saying coronavirus "doesn’t make a distinction between Clackmannanshire or Falkirk".
In a letter to local government minister Aileen Campbell, seen by the Record, GMB organiser Drew Duffy wrote: "We cannot have a situation whereby we have 32 different definitions of key worker in each of Scotland's councils.
"The UK Government has provided clear advice to local government workers in other parts of the UK, in Scotland we have Cosla telling us that they are not a decision making body and we have council workers telephoning their union to ask whether or not their kids will be at school next week.
"We have as you know had no engagement so far from ministers with us, with only a Scottish Government official taking part in Cosla conference calls."
The GMB wants more talks on the treatment of pregnant women, who the union said "should be at home" to avoid the virus.
The union wants a national plan for protective gear against infection, rather than by councils.
Meanwhile, the USDAW union and the Scottish Retail Consortium have written to Swinney to call for retail staff to be included in the list of key workers.
