Turkey's highest administrative court has rejected the main opposition party's bid to appeal the result of the April 16 referendum on boosting the president's powers.

The Republican People's Party, or CHP, is contesting the referendum due to a number of voting irregularities, in particular an electoral board decision that accepted ballots without official stamps. International monitors have also noted irregularities in the voting, which resulted in a narrow win for President Recep Tayyip Erdogan's "yes" camp.

The Council of State on Tuesday ruled against the CHP's request to overturn the electoral board's controversial decision, the state-run Anadolu Agency reported. The court said it did not have jurisdiction over the electoral board's decision.

A previous CHP appeal of the referendum's result to the electoral authority was also rejected.