Teaching union EIS has lodged grievances at two councils after claiming they failed to facilitate phased returns of pupils.
The Educational Institute of Scotland (EIS) said the Scottish Borders and Moray local authorities have also failed to properly consult and reach agreement with unions, in line with Scottish Government guidelines.
Borders pupils went back to school on Tuesday, while the return to classrooms in Moray will happen on Wednesday.
The EIS said a lack of discussion around using the flexibility of a phased return means staff are under “intense pressure” over schools reopening.
It also said the Scottish Borders Council (SBC) grievance asks for a phased return of pupils and said the council has responded by acknowledging the union’s concerns but not the grievance. The union said it will be pursuing the matter.
Larry Flanagan, general secretary, said: “The recent EIS national survey indicated majority support from members for industrial action if required, to ensure the safety of staff and pupils in our schools.
“We will always seek to resolve collective grievances through dialogue but councils such as Scottish Borders need to engage with the EIS and not seek to bypass proper discussions by claiming a ‘corporate decision’ has been made.”
SBC has been contacted for comment.
A Moray Council spokesman said: “We discussed return to school guidance with trade unions throughout the school summer holidays and published this guidance following seven virtual consultations with head teachers prior to the start of term.
“There are arrangements in place across our schools to help pupils and staff phase back to normal in the first few days, including staggered starts and soft introductions to the curriculum, particularly for those in transition years of P1 and S1.”