Speaking in Ankara on Tuesday, Erdogan said the EU had been dragging out Turkey’s accession process for many years.
"That's not how it works. We will do whatever is necessary [in Turkey's interests]," he said.
The president also said Turkey would hold the EU to account over Huseyin Kurt's mistreatment after the referendum.
Kurt was among thousands of Turkish-origin people who gathered in front of their consulate in the Dutch city of Rotterdam to protest against the Netherlands’ ban on Turkish ministers who were prevented from meeting expat voters.
Kurt was bitten by a police dog as officers broke up the protest. Images of the incident made headlines in Turkey.
"We will hold them to account after April 16 for dragging my brother Huseyin Kurt to the ground in the Netherlands," Erdogan said.
On March 11, the Dutch government first canceled a flight by Turkish Foreign Minister Mevlut Cavusoglu and then blocked a convoy carrying Family Minister Fatma Betul Sayan Kaya, forcing her to leave the country under police escort.
The ministers had been due to meet Turkish residents ahead of an April 16 referendum on constitutional changes.
Referring to the incidents, Erdogan said European countries had disregarded all diplomatic norms by not allowing Turkish ministers into their countries.
"They have used every means possible, including a state of emergency,” he said, and noted the irony that Turkey’s own ongoing state of emergency “annoys them”.
Erdogan said that the current Europe was "the racist, fascist and cruel" continent from before the Second World War.
He stressed: "After the presidential system following the referendum on April 16, it will be a different Turkey."
Turkey applied for membership of the EU in 1987; accession talks began in 2005.
However, negotiations reached a stalemate in 2007. The German and French governments have opposed full EU membership for Turkey.
To gain membership, Turkey has to successfully conclude negotiations with the EU in 35 policy chapters which involve reforms and the adoption of European standards.