Campaigners have said up to 2,000 travellers could find themselves in the same position as families evicted or threatened with eviction from illegal sites in Dundalk and Galway.
About 100 people protested at the Louth County Council offices after 23 families were forced to leave the Woodland Park site after officials raised health and safety concerns and fire hazards.
At the Barna recycling facility on the Headford Road north of Galway city, a number of families were given a reprieve on eviction until next Wednesday after spending six months on private property at the entrance to the site.
Based on its most up to date records, the Irish Traveller Movement (ITM) said hundreds of travellers could be at risk of eviction orders as audits on fire risks are carried out by authorities in the wake of t he Carrickmines disaster which left 10 people dead.
"We would have particular worries where the 445 families are in unauthorised sites and the 37 sharing basic serviced bays are concerned, amounting to over 2,000 people," a spokeswoman said.
The ITM also said it is increasingly concerned at local authorities' attempts to house travellers in private rented accommodation.
"There is an over-reliance and increased incidences of this which is not a sustainable solution to the complex issues raised by traveller accommodation and complicated by travellers' limited and arbitrary access to the private rented market," the spokeswoman said.
The Dundalk travellers, mostly from the Quinn-McDonagh families, were living on an unofficial halting site and a number of them moved to a nearby site, next to Dundalk retail park and beside the Inner Relief Road following the eviction.
Homeless services at Louth County Council were closed for the day while the protest took place.
At the Barna site in Galway, the 15 families of young parents with 15 children in total, aged from 11 weeks to nine years, have been on the property for six months.
They had been in housing but moved out when their houses were put up for sale and moved on to the land with caravans.
Sinn Fein president Gerry Adams joined travellers from around the country at the protest in Dundalk, and called for the original Woodland site to be developed to a safe standard.
"There is an unprecedented housing crisis in Louth. Five thousand people are on the waiting list. It is bizarre that the council action has made even more citizens homeless," he said.
"No social or affordable housing was built by the council in 2015. Though the Government did not give any funds out, there is funding available for traveller accommodation."