There have also been events held in areas including Newcastle, Sheffield, Barnsley, Cambridge, Southampton, Bolton, Luton and London.
Plaid Cymru’s Leanne Wood told the rally that the movement needs to be united if they are to successfully oppose the deep cuts of the Con/Dem Westminster Government.
The rally followed an emergency meeting of the Welsh Assembly’s cross-party group for the Public and Commercial Services (PCS) union this morning.
Ms Wood, who represents the South Wales Central region in the Assembly and chairs the cross-party PCS group, told the rally: “This Assembly government is trying to provide the conditions where new jobs can be created – their strategy will be undermined by the savage cuts to jobs that we can expect to follow from today’s announcement.
“If the post-war government in 1945 could build a welfare state when the government faced crippling debt, why is this Con/Dem coalition government insisting that deep cuts are the only option? We’re not buying it.”
She added: “We’ve just held an emergency meeting of the cross-party group for the PCS and we’ve agreed to work together to campaign against these job losses. This movement needs to be united and as strong as it can be – we all have to work together to stand up to the UK government.
“Then we can succeed.”
Further demonstrations will be held in the next few days and the TUC is organising a national protest in London next year.
Dave Prentis, general secretary of Unison, said: “The coalition is taking a chainsaw to our public services and we are under attack, not because of a deficit, but because of an ideology.
“We will build an alliance of all public service unions to break the pay freeze, protect our pensions and stop the cuts.
“If the Government doesn’t listen to us today, they won’t have heard the last of us. If George Osborne’s cuts go through – cuts that could mean a death sentence for our services and our communities – then we will be back.”