BUDAPEST, April 28 (Reuters) - Hungary's outgoing prime minister, Viktor Orban, offered his resignation as leader of his right-wing ‌Fidesz party on Tuesday but a party congress in ‌June will decide whether to accept, a Fidesz lawmaker told local media.

The centre-right ​Tisza party, led by Peter Magyar, defeated veteran nationalist Orban at an election on April 12, ending his 16-year-rule and triggering soul-searching and calls for change within Fidesz.

Fidesz will vote on a ‌new party leadership at ⁠a June 13 congress, the lawmaker, Erik Banki, was quoted by state news agency MTI as saying.

Fidesz ⁠did not respond to a request for comment.

Orban did not speak to the media after a party meeting on Tuesday or ​post on ​his Facebook site.

After the election, ​Orban told the right-wing YouTube ‌channel Patriota on April 16 that as president of Fidesz he took "full responsibility" for his party's defeat and that Hungary's right-wing needed "complete renewal".

On Saturday, he said in a Facebook video that he would not take up his seat in parliament but "return" it ‌to Fidesz.

"I am needed now not ​in parliament but in the reorganisation ​of the right-wing," said ​Orban, who has been a close ally of ‌U.S. President Donald Trump and ​who also won ​endorsements ahead of the election from far-right party leaders in Europe.

He also said on Saturday that the Fidesz party ​leadership wants him to ‌stay on as party leader and he is "ready for ​the task" if the June congress supports him.

(Reporting by ​Anita KomuvesEditing by Gareth Jones)