Mr Sillars, a former SNP MP, has been announced as one of the key speakers at a special conference organised by the No To Named Persons (NO2NP) campaign group.
Aidan O’Neill QC, a lawyer involved in the successful Supreme Court challenge to the policy, will also speak out at the event, which is taking place in Edinburgh on March 20.
It comes after Education Secretary John Swinney announced an ‘’intense’’ three-month consultation on how to make the scheme comply with European human-rights law in September last year.
The consultation was announced six weeks after the UK Supreme Court ruled elements of the policy to be ‘’incompatible’’ with the right to privacy and family life, as set out in the European Convention on Human Rights (ECHR).
NO2NP spokesman Simon Calvert said the group was renewing its opposition because the “Scottish Government wants to press on and provide a replacement scheme”.
He said: “They recently held a consultation or engagement process primarily with those groups which back the scheme.
“We were not invited to attend because we oppose the scheme, even though we represent the views of more than 35,000 supporters and, indeed, majority opinion in Scotland.
“In 2016 ComRes found that only 24% of Scots thought every child should have a state-appointed named person. Almost two-thirds believed it was ‘an unacceptable intrusion into family life’.
“We have now decided to give our supporters a platform to receive important information, to debate and to engage on the key issues which are at stake.”
The named person policy, introduced as part of the Children and Young People Scotland Act of 2014, set out to appoint a single point of contact, such as a teacher or health visitor, to look out for the welfare of all children up to the age of 18.
After the legal challenge, Mr Swinney was forced to act to halt the roll-out of the scheme, which has already been trialled in some parts of Scotland.
It had been due to be introduced across the country on August 31 2016 but Mr Swinney later said he hoped a revised scheme could come into force a year on from that.