BAGHDAD (Reuters) - Iraq's parliament approved the appointment on Monday of a new defense minister, Erfan al-Hiyali, and a new interior minister, Qasim al-Araji, state television said, but rejected nominees for new ministers of trade and industry.

Hiyali, a Sunni, and Araji, a Shi'ite, are filling positions left vacant last year.

Hiyali replaces Khaled al-Obeidi, who was sacked by parliament last year, while Araji replaces Mohammed al-Ghabban, who resigned after a massive truck bomb in central Baghdad in July.

However Prime Minister Haider al-Abadi's nominees for the trade and industry ministries failed to win the necessary votes for approval. Those two positions, alongside the finance ministry, have been vacant since last year.

Hoshiyar Zebari was sacked as finance minister in September following accusations of corruption, which he denied.

Critics have slammed the dismissals of Obeidi and Zebari as politically motivated and warned they risked further undermining security in the country. Iraqi forces are battling Islamic State fighters in the northern city of Mosul.

Industry Minister Mohammed al-Daraji resigned following orders from the powerful Shi'ite Muslim cleric Moqtada al-Sadr who called for protests last year demanding Abadi replace his cabinet with technocrats. Daraji is from Sadr's political camp.

(Reporting by Saif Hameed; Editing by Dominic Evans)