A Labor politician embroiled in the national citizenship crisis has released documents in an effort to clear her name, but concedes being referred to the High Court may be "the only step" left to resolve the uncertainty.

There have been doubts about the eligibility of Justine Keay, the Labor MP for the Tasmanian seat of Braddon, for several weeks but Prime Minister Malcolm Turnbull upped the ante on Wednesday by suggesting she may have to resign.

Ms Keay, who was a British citizen on the night of the election, is relying on the steps she took to renounce her dual citizenship to make her eligible for Parliament.

In February 2016, the Labor Party's legal division notified Ms Keay of the required steps to be eligible as a candidate - but it was not until the election was called in May that she began the renunciation process.