A family member of a passenger missing on Malaysia Airlines flight MH370, holds a poster depicting the flight during a protest near the Malaysian embassy in Beijing on March 8, 2015. GREG BAKER/AFP/Getty Images

As the world's focus turns to the tiny Indian ocean island of Reunion, where a piece of debris that could be part of missing Malaysia Airlines Flight MH370 was found Wednesday, relatives of those on board the missing aircraft have expressed a mixture of caution, pain and anger.

"My initial reaction was I wasn't sure whether to believe it because there have been so many false alarms," said Sarah Bajc, whose boyfriend Philip Wood was a passenger on MH370 when it went missing on March 8, 2014, on a flight from Kuala Lumpur, Malaysia, to Beijing with 239 people on board, in a statement provided to NBC News.

"If it is from the plane than any hope that I might have had that this plane landed safely somewhere is harder to believe," she added. "My thread of hope goes away."

Bajc has been highly critical of the Malaysian government's efforts to locate the aircraft. She was one of a group of passengers' relatives and interested parties that set up an Indiegogo appeal to fund a reward for information leading to the plane's discovery. Bajc wrote on the appeal's page that “the official investigation being run by governments and agencies has failed to find the plane, due to either incompetence or obfuscation.”

"I am still very angry at the country of Malaysia for their lack of efforts to hold anyone responsible for this," Bajc added in her statement "They have failed the world."

New Zealander Sara Weeks, whose brother Paul was on board the flight, told TVNZ that she “felt a bit sick,” upon waking up to the news that wreckage from the flight may have been discovered.

“This whole time we've not known anything, so you still have some hope that something else has happened, that maybe it did land somewhere, maybe the hijack stories are true and they could still be alive. You always have that hope. I guess [this discovery] takes the hope away,” she added.

In contrast, news of the discovery appeared to be too much for some relatives of the missing. Maira Elizabeth Nari, who is the the daughter of Andrew Nari, MH370's chief steward, tweeted that she was choosing to “close her eyes” as she saw MH370 beginning to trend.

K.S. Narendran, whose wife was on MH370 when it disappeared, told CNN that he was reticent to call the discovery a major development.

"I think this is very early days yet. All we know is that a small part has been found. It is still a little early to suggest it does belong to MH370," he said. "I think it is premature to feel that it is all coming to a close or that we are even closer to the truth."

His caution was echoed by Malaysia Airlines themselves. In a statement on Twitter, the airline said they were “working with the relevant authorities to confirm the matter,” adding that “ it would be too premature for the airline to speculate the origin of the object,” which had been discovered in Reunion.