The DA said it would have preferred to receive a "courtesy call" ahead of her attendance. "A courtesy call to alert the DA would have been welcomed".
During her address, De Lille may have justified her appearance in Brandfort, as she quoted Madikizela-Mandela in dismissing her crossing off party lines.
The storm around Patricia De Lille's attendance at an EFF memorial service for Winnie Madikizela-Mandela has thrown open the debate on whether she plans to join a new political party.
Ntsekhe said DA leader Mmusi Maimane was also invited to attend the EFF's memorial, but was unable to attend.
The Cape Town mayor is at loggerheads with the DA and is facing a disciplinary hearing on other matters.
De Lille did not attend a memorial service in the city on Thursday, organised by the South African Religious Forum.
"She either goes to the ANC or the EFF, both with benefits and disadvantages".
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Let's leave the rest for Sunday when we have laid Mam'Winnie to rest.
"She is a former special colleague of Mama Winnie and it is in that capacity that she went to pay tribute to her, and she is not going to allow the fact that she attended the event to become a side issue to that".
Addressing the crowd at the memorial‚ De Lille spoke fondly about Madikizela-Mandela and their relationship.
The DA has, along with the nation, been mourning the death of Mrs Madikizela-Mandela and refuses to be drawn into mud-slinging in her name.it is simply inappropriate. "Patricia worked with Mama Winnie and it's within her right to pay tribute in an appropriate platform‚" he said.
The party will therefore formally ask for an explanation as to her reasons for attending, he said.
She tweeted: "I am so sad tonight".