BANGKOK, July 5 (Reuters) - Thailand's parliament will vote for a new prime minister on July 13, house speaker Wan Muhamad Noor Matha said on Wednesday.

The announcement comes a day after Wan Noor was endorsed as house speaker, a role in which he is able to call for a joint sitting of the country's bicameral legislature to vote on the next prime minister.

The election-winning Move Forward party and populist Pheu Thai trounced conservative rivals in a May ballot, securing 151 and 141 seats in the 500-member lower house, respectively.

Together with six other parties they are expected to propose Move Forward leader, the U.S.-educated Pita Limjaroenrat as the next premier to replace the incumbent Prayuth Chan-ocha.

However, with 312 votes the alliance is short of the 376 votes that Pita needs in the joint sitting, which includes a conservative-leaning 250-member senate, who were appointed during military rule.