Unionist politics should be “re-energised” if a general election is called, the leader of the Orange Order said.
Political influence must be maximised to meet the challenges ahead, grand master Edward Stevenson added.
Thousands of Orange Order members have taken to the streets of Northern Ireland to celebrate the main date in the Protestant loyal order parading season.
Mr Stevenson said: “If we are to indeed see a general election in the next year - there is a real challenge for unionism as a whole in ensuring that we re-engage with non-voters and to re-energise unionist politics as an electoral force with a strong, attractive message.
“This institution has played an important role in the elections of past generations and we must be willing to go the extra mile to help political unionism in the challenges ahead.
“We are a broad church in terms of political views - however, one thing all our members can agree on is that our interests are best served as citizens of the United Kingdom of Great Britain and Northern Ireland.”
The longest parade was in Belfast, where hundreds of Orange lodge members, accompanied by about 60 bands, made their way through the city towards the demonstration field on the southern outskirts. Union flag-waving supporters lined sections of the route to cheer them on.
Irish Senator Neale Richmond watched the parades as a representative of his Government.
He said: “The prospect of someone like me going up 20 or 30 years ago just would have been a non-runner. It would not have been appreciated.
“The atmosphere was quite unique, it was very lively.”