Miss Ladele believes that civil partnerships are "sinful"
Some Christian registrars fear their lives will be made a misery because they do not want to conduct same-sex marriages, a tribunal has heard.
Elizabeth Thatcher, a registrar, told of an unnamed colleague who feared she could be "vilified" as a result.
She gave evidence at a discrimination case brought by Lillian Ladele against Islington Council in north London.
Miss Ladele said she was bullied for refusing to conduct such partnership ceremonies. The council denies this.
Until December 2007 registrars in the borough effectively worked on a freelance basis, meaning they could swap with each other to avoid same-sex ceremonies.
But since then they have been under direct control of the local authority which, it is claimed, has led to far less flexibility about the registrars' responsibilities.
Miss Ladele has claimed she was being effectively forced to choose between her religion and her £31,000-a-year job as a result.
She said she was picked on, shunned and accused of being homophobic for refusing to carry out civil partnerships.
The case, at the Central London Employment Tribunal, is expected to lead to a landmark ruling over whether employees can be required to act against their consciences.
Mrs Thatcher was giving evidence as a Christian and as a Kent council registrar, a position she has held since November 2000.
She shares Miss Ladele's beliefs that civil partnerships are "sinful".
"I have heard of one Christian who has had to resign, but I know of others who have been accommodated," she said.
"She told me that she was terrified about herself or her authority being identified because she could be vilified or the authority put under pressure to remove her."
Miss Ladele told the tribunal there had been times when she was treated in such a hostile manner that "the only way to have dealt with it would have been to have gone up to those people and to have had a fight".
"But I did not do that," she said. "I restrained myself and showed them how to behave [well]."
However Adrian Lynch, for Islington Council, claimed that she had a "distorted recollection" of events and did not properly register her concerns with her managers.
And Miss Ladele's manager, Helen Mendez-Child, denied being abusive or ridiculing Miss Ladele over her views.
In fact, "one gay member of staff felt that she was discriminating against homosexuals", Ms Mendez-Child said.
"I had staff who felt like second-class citizens because of the beliefs that Lillian had expressed," she added.
"I do not believe that she was discriminated against or that she can cite evidence to back it up," Ms Mendez-Child told the hearing, which continues.