In this March 28, 2019 photo, visitors look at a Tesla Model 3 during a press preview of the Seoul Motor Show in Goyang, northwest of Seoul, South Korea. (JUNG YEON-JE / AFP)

SEOUL - South Korea said it is investigating suspected safety issues with vehicles made by US automaker Tesla Inc, which is competing strongly with Hyundai  Motor Co in the South Korean electric vehicle market.

Braking and steering systems including the Autopilot function were part of the investigation, a transport ministry official said

Braking and steering systems including the Autopilot function were part of the investigation, a transport ministry official said on Wednesday.

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The ministry declined to elaborate but South Korean media said Tesla's Model 3 was under investigation, and the probe might take anywhere from six months to a year.

Tesla would cooperate with the investigation, an official at its South Korean unit said.

The US National Transportation Safety Board last year cited driver errors and Tesla’s Autopilot design as the probable cause of a January 2018 crash of a Model S in California.

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In Hyundai's home market, Tesla had its best month in June, with its Model 3 beating Hyundai’s Kona EV, as well as premium models from BMW and Audi.