Merkel, who served as the host leader of this year's summit, said at a news conference that it was up to individual nations to decide who represents them, Bloomberg reported.
"The delegations themselves decide, should the president not be present for a meeting, who will then take over and sit in the chair,” Merkel said, according to the report.
“Ivanka Trump was part and parcel of the American delegation so that is something that other delegations also do. It’s very well known that she works at the White House and is also engaged in certain initiatives.”
A photo of the first daughter sitting beside British Prime Minister Theresa May and Chinese President Xi Jinping surfaced on Twitter, drawing some criticism, including from aides to former President Barack Obama.
Cabinet officials typically replace the president at high-level sessions when a stand-in is needed. Ivanka serves as an unpaid adviser to her father in the White House.
“Ivanka was sitting in the back and then briefly joined the main table when the president had to step out,” a White House official said in response to the photo.
The topic at hand reportedly concerned one of Ivanka Trump's projects, the World Bank finance initiative for women entrepreneurs.
"Unelected"? What does that matter? "Unqualified"? Compared to who? I bet those tweeters thought they were being very clever advancing this particular line of attack. Surely Ivanka sitting in on a meeting of heads of state was absolutely unprecedented and a clear indication of incompetence in the Trump White House.
Instead, Merkel - obviously no fan of Trump - put a damper on the troll party by pointing out the obvious; if anyone in the administration was "qualified" to sit in on a meeting discussing the finance initiative for women entrepreneurs, it was the president's daughter.
How silly do those trolls look now?