Icelanders opposed to the state funding of religion have flocked to register as Zuists, a movement that worships ancient Sumerian gods and – perhaps more importantly – promises its followers a tax rebate.

More than 3,100 people – almost 1% of Iceland’s population – have joined the Zuist movement in the past two weeks in protest at paying part of their taxes to the state church and other religious bodies. Followers of Zuism will be refunded the tax element earmarked for religion.

Icelanders are required to register their religion with the state, with almost three-quarters of the population affiliated to the established Evangelical Lutheran Church of Iceland. There are more than 40 other registered religious bodies that qualify for “parish fees” paid through the taxation system. The amount set in next year’s budget is the equivalent of about $80 (£53) per taxpayer over a year.

“There is no opt-out. Those who are unaffiliated or belong to unregistered religions effectively just pay higher taxes,” said Sveinn Thorhallsson, a Zuist spokesperson. An opinion poll published in September showed 55% of respondents want an end to the system.