TAIPEI/BEIJING (Reuters) - Taiwan issued a maritime warning and airlines canceled some flights as the island braced for Typhoon Talim, which was expected to hit cities including the capital Taipei, before hurtling towards China potentially as a super typhoon.

Talim was expected to gain in strength as it sweeps towards Taiwan's northern cities, including New Taipei, lashing them with strong wind and heavy rain, the Central Weather Bureau said on Wednesday.

Its greatest impact would be felt later on Wednesday and on Thursday, the bureau said on its website, when it was expected to slam into the north and northeast with maximum sustained wind speeds of 137 km per hour (85 mph) and gusts of up to 173 km/h (107 mph).

It had not yet been determined whether the Taiwan government would close financial markets, companies or schools on Thursday. An announcement would be made later on Wednesday if closures were considered necessary.

China Airlines and EVA Airways, Taiwan's two largest carriers, said they would cancel some inbound and outbound international flights scheduled for later on Wednesday. A warning for sea traffic was also issued by the Central Weather Bureau.

Formosa Petrochemical Corp, Taiwan's second-biggest oil supplier, said it had prepared to close its supply port if necessary as Talim approached, although it was waiting for a government directive.

Typhoons are a seasonal routine for Taiwan, but the island has enhanced its preparations and been on guard against the potential for severe and deadly typhoons since Typhoon Morakat devastated the island in 2009.

Morakat was the deadliest typhoon to hit the island in recorded history, killing close to 700 people, most of them in landslides.

As early as Thursday night, Talim could make landfall along the northern coast of Zhejiang province on the Chinese mainland as a strong typhoon, packing gusts of up to 48 meters per second, China Meteorological Administration said in a statement on Wednesday.

Throughout Wednesday and Thursday, strong winds and rain are expected to buffet the coastal areas of Zhejiang and Fujian as well as the East China Sea and Taiwan Strait, the mainland weather agency said.

Talim could strengthen into a super typhoon with winds of 52 meters per second in the late afternoon on Thursday just before making landfall in Zhejiang.

The storm is expected to turn northeast towards Japan on Friday.

As many as half a million people may need to be evacuated if the storm intensifies, according to Chinese media reports.

Separately, Tropical Storm Maring in the south is expected to steadily intensify and become a strong typhoon as it brushes past the southern coast of Hainan province in the evening on Thursday or early Friday.

Earlier this week, Maring had dumped heavy rains in the Philippine capital of Manila and nearby provinces, causing widespread flooding and landslides.

(Reporting by Faith Hung in TAIPEI and Ryan Woo in BEIJING; Editing by Paul Tait and Jacqueline Wong)