Palmer United Party leader Clive Palmer took 10 months to publicly declare he had quit the directorship of three companies linked to Queensland Nickel.
As a federal MP, Mr Palmer is required to update his parliamentary pecuniary interest register within 28 days of a change, which is then published on the parliamentary website.
However, a check of the register found Mr Palmer quit as a director of Queensland Nickel, QNI Resources and QNI Metals on February 16 last year but did not note this until December 10.
The register also showed Mr Palmer had remained a director of the three companies until April 5, 2014.
This is despite telling reporters on several occasions he had not been a director of any of the companies he owns since September 2013 when he entered parliament as the MP for the Queensland seat of Fairfax.
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Mr Palmer is noted as having rejoined the board of the three companies on January 22, 2015, before quitting the directorships again on February 16.
Under parliamentary rules, any MP who "knowingly fails to notify any alteration of those interests to the registrar of members interests within 28 days of the change occurring ... shall be guilty of a serious contempt of the House of Representatives and shall be dealt with by the House accordingly".
Contempt of parliament is rarely pursued by the privileges committee, but can attract a range of penalties from a reprimand to a fine or jail.
Queensland Nickel went into voluntary administration on Monday, following the layoff of 237 workers at its Yabulu refinery on Friday.
Labor leader Bill Shorten says workers' entitlements should be put before any banks or vested interests.
