Unite is holding the gathering in Edinburgh tomorrow after the Church was criticised for telling staff in a letter if they did not agree to new pension terms they would be sacked and re-employed under the new contributions deal.
Industrial action is not being considered but workers will be given legal advice.
More than 220 staff based at the Church's administrative headquarters in George Street received the letter that caused concern last week.
The union said many believed their overall working terms and conditions would suffer if they did not sign, and although the union had been assured staff's general contracts would not be affected it claimed some members were still unsure of their future.
The Kirk said it had moved to reassure workers individually about their concerns over the contributions overhaul, which it said was needed to help cut a £30million deficit in the pension pot.
A Unite spokesman said: "We don't think the members will take (industrial) action, the meeting will be more to reassure them and let them know what legally they can do.
"The wording of the letter shocked people. That is what upset them the most.
"The staff believed from the letter that if they didn't sign then their overall employment terms and conditions could be affected.
"They read it as a threat and thought they would suffer if they didn't sign.
"We have been reassured by the employer this is definitely not the case, the only changes will be to pensions."
A Kirk spokesman said the Church was aware Unite had arranged a meeting for its members at the Church's offices in Edinburgh.
He said: "We would expect any employee representative group to meet its membership once a decision of this nature has been conveyed to enable it to advise their membership accordingly.
"We have encouraged and welcomed consultation with Unite throughout this process.
"Indeed, in response to representations from Unite, we have agreed to increase the new employer contribution rate by 2.5% to a minimum of 11.5%.
"Consultation over the pensions issue has been open, accountable and honest.
"To ensure everyone had a chance to comment, not just those in Unite, we also put in place a staff consultation group, conducting parallel meetings with this body and the Unite representatives."
He said the Church communicated to all staff that the "only matter under discussion" was pension provision and it was not considering any other changes to their terms and conditions of employment.
The Kirk's previous contribution of 21% of a worker's salary without employee contributions was rare.
The move for change comes at a time when pension funds in all sectors are under increasing pressure.
The Church's 11.5% offer without employee contributions was said to be considered a good deal by workers because it outstrips many private sector arrangements, although they had sought 14%.