The church was built in about 1883
A Liverpool church has been placed on the Victorian Society's list of the top ten endangered buildings in England.
The Seamen's Church or Gustav Adolfs Kyrka was built in the late 19th century to minister to Liverpool's large population of Swedish mariners.
Although the church, on Park Road, still has a thriving Scandinavian congregation, it may have to shut down because of a lack of funds.
It is hoped the historic building may be saved from closure.
Run by SKUT, the Swedish Church Abroad, it was built in about 1883 and is one of only three octagonal churches in the UK.
Campaigners want the church to be upgraded to Grade II* listed status, which could offer further protection.
Otherwise they fear it may be closed and "left to rot".
Alex Baldwin, Conservation advisor to the Victorian Society said: "The Gustav Adolfs Kyrka is an extraordinary building.
"A red-brick interpretation of a Scandinavian stave church, it is a striking landmark as well as a key record of Liverpool's maritime history.
"With over 1,500 signatures on the petition to keep the building open, it's clear that the church matters to very many people."
He added: "We urge the Swedish Church Abroad to work with the community so that one of Liverpool's most remarkable churches can continue to be an asset to the city for many years to come."
St Marie's Church on Lugsdale Road in Widnes, Cheshire, has also been included on the list.
The Grade II listed church has been closed for services since January last year.