Bob Beech helps run the Pompey Pals project which looks to remember all those from the city killed in the conflict.
Over the years, the charity has collected a vast store of First World War relics, from machine guns and rifles, to medals and uniforms.
Now Mr Beech has revealed the group is hunting to find a permanent home to display all the items.
He hopes to be able to create the UK’s biggest dedicated museum to all those who fought in the conflict.
But he admitted he has a long way to go and is now appealing for help from the people of Portsmouth in an effort to find a premises.
‘We have got a selection that we know could fill a city museum easily,’ he said.
‘We have hundreds of items. We’d definitely like to create the biggest First World War museum in the UK.’
Mr Beech has already approached Portsmouth City Council for help and has been in talks with the Heritage Lottery to see if a grant could be provided.
He said nothing was set in stone but was optimistic in securing the Pals a new home.
‘The aim would be to create a visitors’ centre and research centre,’ he said.
‘We wouldn’t just house uniforms and Vickers guns – we’d be able to tell the stories behind these items, like the bloke who carried this gun came from Cosham.’
The move comes after the group staged a major commemoration event in Portsmouth earlier this month to mark all the soldiers from the city killed in the Battle of the Somme.
The 141-day battle is marking its centenary this year.
More than 750 men from Portsmouth’s two Pals battalions were killed or injured in the fight.
Among those to lose their lives include 15-year-old George Jakes.
He was revealed as the youngest soldier from the city to die in the war after years of research by the Pompey Pals.
To help with the museum, visit pompeypals.org.uk