More than 700 mainly young Protestant men have been convicted of rioting in protests linked to parades and the union jack dispute in Belfast, it has emerged.

The news came ahead of a potentially violent standoff involving Ulster loyalists and a banned Orange Order march in Belfast.

As loyalists were preparing to light their bonfires on the eve of the 12 July – the climax of the marching season – Northern Ireland's justice minister, David Ford, told the Guardian that he was concerned that more and more young Protestants were joining the ranks of those already convicted of public order offences.

"I really do not want to see any more people, mainly young loyalists under the age of 23, ruining their lives and their future prospects by being convicted through the courts and having criminal records. But the police and the courts will take a robust stance against those involved in any more rioting and disorder," he said.

The justice minister's warning highlights the new radicalisation of Protestant working-class youth caught up in the violent protests against banned loyalist marches and the ending of a policy of flying the union flag atop Belfast City Hall.

His concern over the number of younger people, most of them with barely any memory of the Troubles, coincides with claims by loyalist political veterans that youth in working-class Protestant redoubts have become radicalised and politicised through these disputes.

Ford said the 700 people who have been processed through the courts were detained over the last 18 months of street disorder, mainly in Greater Belfast.

"They are in the main those arrested on public-order offences linked to protests over flags and parades. They are in the main under the ages of 23 or 24. The majority of those who have been arrested were detected rioting on CCTV cameras. Which you would hope would be a deterrent to others not to follow down the same path," the justice minister said.

Ian McLaughlin, of the Ulster Political Research Group in west Belfast, which is linked to the Ulster Defence Association paramilitary group, said veterans of loyalism had noticed the impact of controversies such as Saturday's ban of an Orange Order parade along Belfast's Crumlin Road on younger people who either born when the paramilitary ceasefires were declared or had little or no memory of the Troubles.

"The recent flags dispute and parading issues has, we believe, awakened a new breed of young loyalists who are demanding to know their history, warts and all," McLaughlin said. "They are becoming increasingly aware of governance, or lack of it, and are politicising themselves to be part of future change. They are confident in learning of their own past and confidently challenge others on theirs!"

McLaughlin claimed that anger among young loyalists had shaken them out of their political apathy. For the last two decades electoral turnout in Protestant working-class areas, especially among younger voters, has been far lower than in republican districts.

He said: "Educating our young to exercise their democratic right to vote is pivotal in moving forwards, far too many in the past simply refused to vote as they felt it was pointless."

The West Belfast loyalist accused Sinn Féin and other rival republicans of waging a "cultural war against any semblance of Britishness" in Northern Ireland, which he said had galvanised the younger part of his community.

Over the last year 820 policemen and women have been injured in clashes with loyalist demonstrators – almost one quarter of the Police Service of Northern Ireland's frontline officers.