The Peterborough MP, who faces a possible prison sentence, had already been suspended and urged to stand down by the party after being found guilty at the Old Bailey in December.
However, Onasanya has indicated she hopes to remain as MP for her constituency.
In an article for the Peterborough Telegraph she said: "While it has been a successful year fighting back against these injustices, there is still much more to be done, and you can rest assured that I will continue to do so as your representative in the corridors of power."
Labour confirmed on Friday that she had been expelled before Christmas, after party chairman Ian Lavery told her local paper, the Peterborough Telegraph, that it would run a candidate in any by-election.
Onasanya, a 35-year-old solicitor, was convicted after a retrial of colluding with her brother Festus after her car was clocked going 41mph in a 30mph zone in the village of Thorney near Peterborough in July 2017.
The court was told that she was sent a Notice of Intended Prosecution (NIP) to fill out, but it was sent back naming the guilty driver as Aleks Antipow, an acquaintance of her brother Festus, who was away visiting his parents in Russia.
Festus pleaded guilty to three counts of perverting the course of justice over speeding, including over the 24th July incident.
Onasanya has compared her plight to Jesus and maintained her innocence since the news broke of the case.
The Times reported that in a Whatsapp message to other Labour MPs Onasanya wrote: "I am in good biblical company along with Joseph, Moses, Daniel and his three Hebrew friends who were each found guilty by the courts of their day.
"While God did not save them from a guilty verdict he did save them in it and ensured that their greatest days of impact were on the other side of a guilty verdict.
"Of course this is equally true of Christ who was accused and convicted by the courts of his day and yet this was not his end but rather the beginning of the next chapter in his story."
Onasanya took the hyper-marginal seat with a majority of just 607 from Tory Stewart Jackson at the 2017 election just 18 months ago.
Parliamentary rules require the removal of an MP who is jailed for 12 months or more.
But if the sentence is less than that a recall petition can force a by-election if it is signed by more than 10 per cent of the electorate in the Cambridgeshire seat.
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