The official garda estimate for the attendance at the anti-austerity protest in Dublin was around 10,000 people.
Earlier, garda sources on the ground told RTÉ news that at the height of the protest they estimated there were around 18,000 people taking part.
However, the Garda press office has insisted that the figure based on information from the Garda helicopter was 10,000.
The march was organised by the Dublin Council of Trade Unions.
Other groups were attending protesting over various cutbacks.
The aim of the protest was to highlight the impact of the Government's policies of austerity and cuts.
A garda helicopter was circling over the march.
The President of the Irish Congress of Trade Unions joined in calls for a general strike in protest at austerity and cutbacks.
Eugene McGlone told a crowd the steps required to organise a strike starting in individual workplaces.
Mr McGlone was initially heckled when he took to the platform.
Other speakers echoed the call for a general strike that would shut the country down.
SIPTU President Jack O'Connor has said that while he is not necessarily opposed to a day of action against austerity, unions would have to be able to convince the overwhelming majority of workers that the objectives they were advocating were achievable and were a better alternative.
He said that they still had a lot of work to do to reach that point.
However, he said that if that amount of support could be mobilised, the trade union movement might be able to achieve its aims through negotiation without the need for actual industrial action.
Mr O'Connor was speaking after Mr McGlone called for a general strike at today's anti-austerity march.
The SIPTU leader criticised what he called fascist behaviour at today's protest when Mr McGlone was heckled by members of the crowd.
However, a number of other senior trade unionists dissociated themselves from Mr McGlone's call for a general strike - describing it as a "solo run".
The organisers of the pre-Budget anti-austerity protest have condemned what they describe as "the divisive attack" of the Mr O'Connor on a section of the crowd.
In a statement, Councillor Brid Smith said: "Nobody orchestrated any heckling - it was a spontaneous outburst of anger at the inaction of union leaders.
"Some highly-paid union bosses appear so much out of touch with the anger of their own grassroots that they see conspiracies everywhere," she added.