A union leader says she is hopeful schools will close after Friday so children can isolate before Christmas.
Director of NAHT Cymru Laura Doel said she was hoping to meet with Education Minister Kirsty Williams on Thursday afternoon “as a matter of urgency”.
Families with children have been told to consider “pre-isolating” at home for 10 days before Christmas if they are planning to see elderly relatives.
Pupils in Blaenau Gwent had their last day in the classroom on Wednesday.
Bridgend currently plans to follow Caerphilly and Rhondda Cynon Taf councils in closing schools early on 16 December.
But Health Minister Vaughan Gething has previously said harm had already been done to children when schools were closed, highlighting the mental health impact particularly among secondary school age children.
Most Welsh local authorities have said schools should remain open until 18 December, despite calls from some unions to end lessons early.
Ms Doel told BBC Radio Wales: “I think we’ll have the conversation this afternoon and I am hopeful that the minister who has, up until this point, always acted on the government health and safety guidance, will act upon this guidance today…
“I think parents are going to vote with their feet anyway.”
Following a report by the Welsh Government’s Technical Advisory Group (TAG) on Tuesday, NAHT Cymru wrote to Kirsty Williams calling for blended or distance learning for the final week of term (14-18 December) for all school pupils.
“Self-isolation remains of paramount importance for anyone with Covid-19 symptoms,” it said.
“The best way to protect older family members is not to expose them to potential infection, no matter how well-intended the reason for contact…
“No direction from the government on this issue risks large numbers of families making their own decision to take children out of school and once again will result in a mixed economy across Wales, with LAs making their own decisions based on local circumstances.”
The Welsh Government has been asked to comment.
Plaid Cymru health spokesman Rhun ap Iorwerth said “nobody wants to see schools close” from an educational perspective but added: “Evidence is pointing in a very clear direction.”
He told BBC Radio Wales Breakfast: “If children mixing in schools creates more chance of passing it on to grandparents, then that [closing schools] will make sense.”