Jami-Lee Ross opens up for first time since the drama of 2018.

Former National MP Jami-Lee Ross has spoken for the first time about the dark days before his compulsory admission to a mental health facility.

Talking exclusively to Stuff and Newshub, Ross has made explosive new revelations - including that a text from an MP he had an affair with is now the subject of a police investigation.

Police confirmed in a statement they were investigating a text message sent to Ross.

But Ross says he is now focused on the future and will return to Parliament in February to resume his political career, where he hopes to have renewed purpose as a voice for others suffering depression and mental illness.

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* Jami-Lee Ross: Controversial from the start

Ross' political career ended in tatters last year when he was expelled from the National Party following accusations he actively undermined leader Simon Bridges and leaked information about his travel expenses. Ross continues to deny he was the leaker.

CHRIS MCKEEN/STUFF Police have confirmed they are investigating a text sent to Jami-Lee Ross last year before he went into hospital.

After weeks of turmoil in the public eye Ross was admitted to Middlemore Hospital's Tiaho Mai mental health unit.

His only public appearance since that night has been at an official function at Tiaho Mai to thank staff for their care.

Describing the events of the night that led to his admission Ross says he was at rock bottom, and friends and family had been increasingly worried about his state of mind throughout the week.

There had already been two previous occasions that week when police were out searching for him.

"In the middle of the night Wednesday I had the police searching for me and they were in my apartment in Wellington and the mental health crisis team was called as well.

By the time we got to Saturday I was feeling so isolated I was feeling so worthless I just didn't feel like I had much left to live for.

"I felt like I had lost my personal life. I felt like I had lost my professional life, I felt like the whole world was against me."

Ross says there had been warning signs earlier in the year that all was not well and he had "cracked" after receiving a text from a female colleague.

He says she told him in that text to kill himself.

The night police picked him up he had texted her telling her "you get your wish" and that was what had triggered the call out leading to his admission to hospital.

Earlier that day his wife Lucy, fearful of his state of mind, had suggested that it would be better if he didn't see his children that day.

"I just didn't feel like existing many more, I didn't feel like I had anything left. So on that night the police were contacted. I didn't know at the time but they had deployed the police dogs, there was a police helicopter, there were ground units looking for me, they had stopped the train on the train tracks because I told my wife that I was on train tracks. "

It was the thought of his children that saved him, Ross said.

Police took him to Waikato hospital and they decided he needed to stay, Ross said.

"It wasn't till I woke up the next morning. I was in this room, it has a mattress, and a stainless steel toilet fixed to the wall, the door was locked, I couldn't get out. I had a cellphone; that was the point at which I was looking around the room going 'oh my god...what has happened, what have I done, how did I get here'. And I just broke down...that was when they saw me and decided they needed to keep me in properly."

He was formally sectioned under the Mental Health Act and detained for several days, Ross said.

He was speaking out now in part because of his experience there.

"The people that worked there are so amazing; so kind and compassionate and caring and their sole focus is on your well being. I wished I had asked for help earlier...wish I had sought and gained that help months earlier because we could have avoided everything."

Ross says he made some bad calls during that period but the National leadership had also "piled on the pressure" that led to his admission.

CHRIS MCKEEN/STUFF Jami-Lee Ross is planning a return to politics this year after a tumultuous 2018.

"I don't blame the leadership for piling on the pressure, they were doing what they knew how to do with the skill set they had and when it came to politics versus someone's well being they made a call politicians make - you've got a political problem, you sort out the political problem and that is their job. "

But the collateral damage had been huge, including to his wife and family.

"I think we need in the future to be kinder when it comes to people's well being in Parliament."

In the days following his release from hospital he had been too ashamed to be seen in public but had been overwhelmed by the compassion and public support shown him.

He had also been overwhelmed by the number of people contacting him to talk about their own experiences with depression and mental illness.

That had given him purpose as an MP.

"I'm touched by the people who have contacted me, mostly on Facebook, wanting to tell me their story. And if I can show them that even someone in public life can reach the depths and dark space but then rebuild their life and come out the other side, and not have a mental health challenge define them, then that gives me strength and a purpose and a reason to help them as well."

In a statement, a National Party spokeswoman said they were not aware of a police investigation. She said the party had sought expert medical advice and offered its full support to Ross.

WHERE TO GET HELP:

1737, Need to talk? Free call or text 1737 to talk to a trained counsellor

Depression.org.nz - 0800 111 757 or text 4202

Lifeline – 0800 543 354

Suicide Crisis Helpline – 0508 828 865 (0508 TAUTOKO)

Kidsline – 0800 54 37 54 for people up to 18 years old. Open 24/7.

Youthline – 0800 376 633, free text 234, email talk@youthline.co.nz or chat to someone online.

Rural Support Trust - 0800 787 254

Samaritans – 0800 726 666

What's Up – 0800 942 8787 (for 5–18 year olds). Phone counselling available Monday-Friday, noon–11pm and weekends, 3pm–11pm. Online chat is available 7pm–10pm daily.

thelowdown.co.nz – Web chat, email chat or free text 5626

Anxiety New Zealand - 0800 ANXIETY (0800 269 4389)

Supporting Families in Mental Illness - 0800 732 825.

If it is an emergency click here to find the number for your local crisis assessment team. In a life-threatening situation call 111.