A ministry worker is warning believers to be on the look-out for a religious group he believes is targeting homes in Sydney's inner-west in the run-up to Easter.

"In the space of about 2 weeks I ran into them twice - once in Newtown and then they door-knocked my home in Marrickville," says Mr Cameron Blair.

Mr Blair heads the Christians by Design ministry which is part of the Fellowship for Evangelism in the Visual Arts (FEVA) which is based in Petersham Evening Church.

He says members of an organisation called the Church of God in Burwood have been contacting families in his area with a message that falls far short of the gospel.

"The first couple that approached me explained they were about because of Easter," he says.

"The line they were pushing is that the Passover is a necessary thing for Christians to observe, just like the Israelites. I asked them a few times just to be clear and they were dead certain. You had to keep the Passover to be saved."

Mr Blair described the group's approach as appearing very Bible-based, but those he talked to were not very receptive to Paul's warnings to the Galatians.

"I talked about adding things to the gospel, and once they realised I was opposing them, they very quickly backed off and walked away," he says.

Mr Blair has taken the extraordinary step of warning his ministry members via email to be careful of being taken in by the Burwood-based church.

His research has revealed it is associated with an international group known as the "Church of God 7th Day'.

This organisation does teach that "justification from sin is through Jesus Christ alone' but it also maintains that certain laws must be observed.

The "Church of God 7th Day' believes in the necessary keeping of an Old Testament-style Sabbath, the performance of laws relating to clean and unclean meats, and the annual observance of a form of the Lord's Supper.

The consumption of alcohol is forbidden and baptism by full immersion is necessary for the remission of sins.

"From what I've heard from them, these people are actually adding regulations, rules and laws on top of the gospel of grace and that's a very serious thing," Mr Blair says.

"I didn't really think there were Christians out there who really believed you had to keep the letter of the law to be saved. I was really taken aback. I was upset because they were not only teaching the wrong thing, they were being deceived themselves."

Christians by Design is encouraging its member to be kind and respectful to members of the Church of God in Burwood if they meet them but not to be afraid of engaging them with the Bible.

Photo by Mr Lynch