ANKARA (Reuters) - Turkey's parliament approved Sweden's NATO membership bid on Tuesday following more than four hours of debate, clearing a last major hurdle to expanding the Western military alliance after 20 months of delays.

President Tayyip Erdogan's ruling AK Party, its nationalist MHP allies, and the main opposition CHP voted in favour of the bid in the general assembly, while opposition nationalist, Islamist and leftist parties voted against it.

Erdogan will sign the bill into law, likely in coming days, thus ending a lengthy process that has both frustrated some of Ankara's Western allies and enabled it to extract concessions.

Hungary remains the only NATO member yet to ratify Stockholm's accession.

(Reporting by Huseyin Hayatsever, Writing by Tuvan Gumrukcu; Editing by Jonathan Spicer)