Grace Nathan misses her mum every day.

"She was the person in our family that held us all together," Ms Nathan said.

"She was the person who was a constant in my life. She was always there for me, for my sister. Our dreams were always her dreams."

For almost four years, Ms Nathan has been waiting and hoping. Hoping for answers about what happened to her mother Anne Daisy and the other 238 passengers and crew on board Malaysia Airlines flight MH370.

The plane disappeared on March 8, 2014, on a flight from Kuala Lumpur to Beijing.

"Not understanding what was going on in the plane, not knowing, or maybe never knowing what my mother was feeling, just being in constant limbo has been something that is very, very difficult to live with," Ms Nathan, who lives in Kuala Lumpur, told 7.30.

A three-year search for the wreckage in the southern Indian Ocean was suspended early last year, but now the search is set to resume, based on new research by CSIRO oceanographer Dr David Griffin.

Ms Nathan has mixed emotions about what might be revealed in the coming weeks or months.

"I'm relieved that the search is finally back on," Ms Nathan said.

"We fought so hard ever since the plane disappeared for the search to continue. But at the same time it's so hard to be optimistic because at every single junction in the past we've always been met with disappointment.

"Every search has returned empty. We've always been faced with more and more bad news."

'Are we going to find you today?'

Sorry, this video has expired Cathy and Bob Lawson were on missing flight MH370.

Jeanette Maguire from Brisbane has endured the same frustration and anguish. Her sister and brother-in-law, Cathy and Bob Lawson, were also on the ill-fated plane.

"We can't move on," Ms Maguire said.

Jeanette Maguire's sister and brother-in-law were on MH370. ( ABC News )

"When you go through grief, you generally get to say goodbye to people, you can go to a funeral, you see the coffin.

"We haven't got any of that. We are not at peace with ourselves and you live every day going, 'I wonder where they are'."

Ms Maguire said news of the search restarting was "obviously very heart-wrenching".

"We are back on the roller coaster," she said.

"I still get out of bed every day and look at the sky and I think, 'Is today the day? Are we going to find you today?'

"We have to find them. The likelihood of getting anyone home is non-existent, but to know where they are brings us closer.

"It will help us to get the peace that we need."

'I really hope the plane is found'

Grace Nathan, right, wants answers about what happened to her mother, Anne Daisy, left. ( Supplied: Grace Nathan )

Ms Nathan is hopeful but at the same time anxious.

"Finding the plane would be very painful for us — a painful realisation that this flight has ended in such a tragic way," she said.

"But also I believe it is a necessary evil, because if we don't find the plane then when will our healing really properly begin?

"How will we begin to attain closure? And more importantly, when will all the questions be answered?

"It's something that must happen. I really, really do hope that the plane is found."