A complaint has been made to the Law Society of Northern Ireland over Sinn Féin MP John Finucane attending an IRA commemoration.
It was submitted by Roger Lomas, a Conservative Party member whose late father was a former secretary of the Law Society.
He claimed Mr Finucane, who works part-time as a solicitor, brought his legal profession into "disrepute" by attending the memorial event in south Armagh.
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Sinn Féin was approached for comment.
A Law Society spokeswoman said: "The Law Society does not comment publicly on any complaints it receives."
Mr Finucane was the main speaker at the South Armagh Volunteers Commemoration in Mullaghbawn earlier this month.
His decision to address the event prompted anger from victims' representatives and rival politicians who cited the many murders perpetrated by the IRA's South Armagh unit during the Troubles.
But Sinn Féin accused the DUP of whipping up a controversy to distract from the party's role in the ongoing political impasse at Stormont.
The republican party said the event has been held for 13 years and asked why it has not prompted such a reaction in the past.
Mr Finucane said the right to commemorate the dead "should apply without prejudice to every section of the society which we now live in today".
The Law Society is the professional body for the solicitors' profession in Northern Ireland. It acts as a regulatory authority governing the professional conduct of solicitors.
Mr Finucane and his Belfast-based law firm appear on the Law Society's directory of solicitors.
In his complaint, seen by Belfast Live, Mr Lomas claimed the Sinn Féin MP's involvement in the south Armagh commemoration was "demeaning to the legal profession".
He wrote: "Mr Finucane in my opinion should choose between his law profession and that of being a politician rather than bring 'politics' into the realms of the legal profession so publicly."
Mr Lomas said his late father Sydney Lomas, a former secretary of the Law Society from 1972 to 1985, believed in the "highest standards of professional conduct".
The former Tory election candidate said he believed his father and his generation of solicitors would regard Mr Finucane's involvement in the republican commemoration as "disrespectful".
Speaking at the memorial event, Mr Finucane said everyone has "the right to remember and the right to commemorate".
The North Belfast MP spoke of his father's murder during the Troubles as he stressed the importance of remembering lost loved ones.
Pat Finucane, who was also a solicitor, was gunned down by loyalist paramilitaries inside the family home in north Belfast in 1989.
Mr Finuance said: "There is nothing to celebrate in conflict or in our difficult and painful past, but to commemorate those we have loved and lost is a right which everyone, including every single one of us gathered here today, is entitled to, and we do so with dignity and with pride.
"And while there are very different and often conflicting perspectives of the causes of conflict, conflict is thankfully now a thing of the past.
"So today we remember with pride the many Irish republicans who gave or lost their lives, with deep sympathy for their grieving families and also respectful of all those who continue to suffer the grief and trauma of conflict."
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