Taiwan on Sunday decommissioned the last 20 of a fleet of ageing missile boats as part of ongoing efforts to modernise its military forces against former rival China, officials said.

The navy bid farewell to the 50-tonne Seagull-class missile boats during a ceremony held in the southern Tsoying naval base, more than three decades after they had been put into service.

The Taiwanese navy first built the missile boats, reportedly an imitation of Israel's Dvora-class patrol boats, in the late 1970s and later mass produced them in the early 1980s.

The navy had thought the fleet, numbering around 50, would act as "hit and run" boats should a conflict break out in the Taiwan Strait.

With a maximum speed of 74 kilometres (46 miles) per hour, each of the boats was armed with Hsiungfeng I (Brave Wind I) ship-to-ship missiles.

The Seagull boats have now been replaced by 30 missile boats built under the so-called "Kuang Hwa No 6 Project" launched in 2000.

Each of the 171-tonne vessels is armed with four Hsiungfeng II missiles, an improved version of the Hsiungfeng I.

Ties between Taiwan and China have eased markedly since Ma Ying-jeou of the China-friendly Kuomintang party came to power in 2008, ramping up trade and allowing in more Chinese tourists.

But Beijing still refuses to renounce the use of force, even though Taiwan has been self-governing since the end of a civil war in 1949, prompting the island to continue to modernise its defence forces.