Plaid Cymru's Gareth Jones has invited councillors from all groups to form an administration.
But the party's chief executive has said it is not going into coalition with the Conservatives.
Gareth Clubb said the approval of the party nationally was needed before they strike a deal with other parties.
The Tories, unlike Labour, are willing to join Mr Jones' administration.
When asked by BBC Wales on Thursday if he was on track for a cabinet of Plaid Cymru, Conservative and independent councillors, he replied: "Yes."
It comes during a general election campaign where Plaid leader Leanne Wood has promised to "defend Wales against the Tory attacks".
She has previously ruled out working with the Tories in the assembly.
Plaid Cymru chief executive Mr Clubb said: "Plaid Cymru is not entering into coalition with the Conservatives on Conwy council.
"Any decisions involving Plaid Cymru council groups entering into deals with other parties need to be approved by the party nationally."
At the time of his appointment to leader of the council, Mr Jones said: "Coalitions shunt others to a position outside the ruling body. It's not right to keep any group out of office.
"We need to develop an inclusive style of administration which respects what the people of Conwy voted for."
No one party has a big enough majority to secure overall control.
Plaid councillors will need the approval of their national executive committee (NEC) before striking a deal with the Conservatives.
The NEC is due to meet at the end of June, after the general election.
A cabinet of Plaid, Tory and independent councillors could be formed in Conwy, the leader of the council has said.