NEW YORK, USA (AP) —Nearly every morning since their father’s stunning victory on Election Day, three of Donald Trump’s grown children walk through the Trump Tower lobby and board an elevator. But are Don Jr, Ivanka and Eric going to the campaign office on the 5th floor? Their business offices on the 25th floor? The president-elect’s penthouse on the 56th floor?

That uncertainty highlights the multiple roles the children play for their father. For the past year the lines were constantly blurred between political campaign and business empire, raising questions about a possible conflict of interest between Trump’s White House and his sprawling business interests.

The children are poised to wield incredible influence over their father, even if they don’t follow him to Washington. Trump said consistently during the campaign that if he won, those children would stay in New York and run his business. But the three — plus Ivanka’s husband, Jared Kushner — were all named to the transition team’s executive committee.

So far, they’ve been heavily involved in shaping the new Administration. They’ve sat in on meetings and taken late night calls from their father. They advocated for making Reince Priebus, the Republican National Committee chairman, the White House chief of staff. They counselled against bringing back Corey Lewandowski, Trump’s first campaign manager, who was fired in June on their advice.

On Thursday, Ivanka Trump and Kushner were present for the president-elect’s meeting with Japanese Prime Minister Shinzo Abe at Trump Tower.

Trump has insisted he will build a wall between his White House and his company by placing his holdings into a blind trust, but with his children as its trustees. Federal requirements are that independent outsiders run such trusts.

“We are in the process of vetting various structures with the goal of the immediate transfer of management of The Trump Organisation and its portfolio of businesses to Donald Jr, Ivanka and Eric Trump as well as a team of highly skilled executives,” Trump spokeswoman Hope Hicks said. She said the structure “will comply with all applicable rules and regulations”.

Trump’s company is the largest business portfolio to belong to a modern sitting president. Federal ethics rules would allow Trump to run his business interests from the White House, or, perhaps more likely, influence decisions made by his children.

That raises conflict of interest concerns: For example, Trump could set domestic policy while making deals abroad that could affect his corporation, even if it were technically in his children’s hands.

Kellyanne Conway, a senior adviser, disputed the idea that the Trump children’s involvement in the transition could lead to a breach of trust.

“You’re presuming that they are doing certain things that they should not be doing,” Conway said. “They are his children. And they’ve been his business colleagues for a long period of time. They obviously will support their father as president.”

But the potentially problematic entanglement revealed itself this past week when Ivanka Trump’s company promoted a US$10,800 bracelet she wore during a 60 Minutes interview on CBS. The spokeswoman for the company later apologised.

The children, who were not made available for interviews, are limited in what formal role they could take in a Trump Administration.

Congress passed an anti-nepotism law in 1967 that prohibits the president from appointing a family member to work in the office or agency they oversee. The measure was passed as a reaction to President John F Kennedy appointing his brother Robert as attorney general.

But the law does not appear to prevent the children — or Kushner, who is one of Trump’s closest aides and is said to be weighing a White House role — from serving as unpaid advisers or providing informal counsel.

The three grown children — whose mother is Ivana Trump, Trump’s first wife — delivered well-received speeches at this summer’s Republican National Convention in which they tried to humanise their father.

Don Jr and Eric were staples on conservative radio and on the road, trekking to campaign offices and small rallies across battleground states like Ohio and North Carolina. Ivanka Trump, meanwhile, was utilised in some of the campaign’s biggest moments, including introducing her father before his convention speech, unveiling his family leave plan and campaigning across the crucial Philadelphia suburbs.

Another daughter, Tiffany Trump, a recent college graduate whose mother is Trump’s second wife, Marla Maples, also made appearances on her father’s behalf. Trump’s youngest child, 10-year-old Barron, whose son is the president-elect’s current wife, Melania, is enrolled at a private Manhattan school.

Eric and Ivanka were the subject of some embarrassing headlines when it was revealed that they were not registered to vote in time for their father in the New York primary. And Don Jr has received criticism for tweeting images likening Syrian refugees to a poisoned bowl of Skittles candy and a cartoon character appropriated by white supremacists.

But now they stand poised to be the most influential presidential children in decades, as recent White House offspring have been far younger than the eldest Trump children, who are all in their 30s. During the campaign Eric Trump insisted that the children’s main focus was the company. “We’d always be one phone call away if needs it,” the younger Trump told The Associated Press in May. “We’d do anything for the man.”

A look at Donald Trump’s five children

NEW YORK, USA (AP) — • Donald Trump Jr Age: 38 Mother: Ivana Trump

Personal: Married with five children

Trump Organisation Title: Executive Vice-President of Development & Acquisitions

Campaign Role: Spoke at Republican National Convention; made frequent campaign appearances and interviews for his father.

• Ivanka Trump Age: 35 Mother: Ivana Trump

Personal: Married with three children T

rump Organisation Title: Executive Vice-President of Development & Acquisitions

Campaign Role: Introduced her father at Republican National Convention, helped craft campaign’s family leave and child care policies.

• Eric Trump Age: 32 Mother: Ivana Trump

Personal: Married

Trump Organisation Title: Executive Vice-President of Development and Acquisitions

Campaign Role: Spoke at Republican National Convention; made frequent campaign appearances and interviews for his father.

• Tiffany Trump Age: 23 Mother: Marla Maples

 Personal: Graduated from University of Pennsylvania in 2016

Trump Organisation Title: N/A

Campaign Role: Spoke at Republican National Convention

• Barron Trump Age: 10 Mother: Melania Trump

Personal: student at private school in Manhattan

Trump Organisation Title: N/A

Campaign Role: Appeared on stage at Republican National Convention and father’s election night speech.