(Adds details on sales, outlook) Aug 24 (Reuters) - Australia's...

(Adds details on sales, outlook)

Aug 24 (Reuters) - Australia's Viva Energy Group (VEA) reported an over four-fold rise in its half-year profit on Tuesday, helped by a rebound in fuel demand, and said it would conduct a capital return of about A$100 million ($72.11 million) to shareholders.

The fuel supplier also said it is looking to conduct an on-market buy-back of up to A$40 million worth of shares.

Australia's control of the COVID-19 pandemic earlier this year had driven a revival in businesses of Viva and larger rival Ampol (ALD) , but they now face risks from a new wave of restrictions prompted by the fast-spreading Delta variant.

Viva warned that the recent capital city lockdowns would likely hurt retail fuel volumes for the rest of the year, with curbs in Victoria and New South Wales impacting demand and refining production.

The company's profit after tax for the six months ended June 30 was A$111.9 million ($80.72 million) on a replacement cost basis, while it also declared an interim dividend of 4.1 Australian cents per share.

Its sales volumes for the six-month period rose to 6.7 billion litres, from 6.4 billion litres a year ago. ($1 = 1.3862 Australian dollars)