A Queensland couple has vanished while travelling interstate, leaving their family “beyond worried”.

Leannedra Kang, 25, and her partner, Takahiro Toya, 26, failed to board their return flight from Launceston, Tasmania to Brisbane on Wednesday.

The pair is believed to have travelled to the St Helens or Scamander area in a rental car.

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Police said the white Toyota Corolla with registration L67GW has not been returned.

Kang’s sister, Cassandra, told 7NEWS.com.au the last time anyone spoke with her was about 8.50pm on Tuesday, which was also the last day she was seen active online.

“It would be unusual for her to go no-contact, she’s usually very active on social media,” Cassandra said.

Another sister, Alex Andra, posted on Facebook that Kang’s last known location may have been North Hobart or Goshen, an area off the route of her planned itinerary.

“Please let me know if anyone has been in contact with her or seen her,” she wrote.

“My family is beyond worried.”

Tasmanian Police are urging anyone who may have seen the couple or the vehicle, or knows of their whereabouts, to come forward.