The Hurstville couple aboard the ill-fated Malaysia Airlines flight had two young children who were living with their extended family in China.
Yuan Li, 32, and Naijun Gu, 31, from Sydney's south, were believed to be on their way to Beijing to spend time with their children, a baby and a toddler.
Jane Tran, who works for the couple's Sydney accountant, Jeffrey Todd & Associates, said staff were in shock.
She said the children lived with their grandparents in China and that the couple travelled there frequently to visit.
"It's so sad," she said. "They were a nice couple, very hard working. I can't imagine how sad their families must be."
The couple had been beset by business problems, selling their Sylvania home and their petrol station, Metro Petroleum in Miranda, last year.
Liquidator Schon Condon was appointed to wind up their company, Y & J Australia, on February 28.
Mr Condon said the couple had contested winding-up proceedings at length but were unsuccessful and he had planned to meet them when they returned from China.
"We hope the outcome is better than what seems likely," he said. "Obviously the situation is of grave concern."
He said he would proceed with identifying the company's assets as part of the winding-up process.
"We will find out what assets the company has and what has happened to those assets, whether they have been dealt with legitimately or illegitimately," he said.
"Our role is to deal with the entity that is the company so that role remains regardless of the fate of the owners. The directors are the mouthpieces of the company. If they are no longer capable of telling us anything, that makes it difficult."
Company records show Mr Li was born in Beijing and Ms Gu in Shanghai. It is believed they met while studying in Sydney.
They registered their business in 2007 and took over the petrol station business K & J Petroleum in 2009, the same year they bought their townhouse in Koorooma Place, Sylvania.
They sold the townhouse in November last year and moved to an apartment in Hurstville.
Real-estate agent Ron Di Donato said he had never met the couple and sold the townhouse on behalf of the National Australia Bank in November.
The Malaysia Airlines aircraft was carrying 227 passengers and 12 crew from Kuala Lumpur to Beijing.
An extensive air and sea search failed to uncover any wreckage from flight MH370 on Monday.
Do you know the couple?