Victoria Police have issued a warant for former Ministry of Transport manager Joanne Harrison's arrest.

Australian police have issued a warrant for New Zealand Ministry of Transport fraudster Joanne Harrison's arrest over a fraud case across the Tasman - but may have to wait until she finishes her jail-term here.

Harrison, also known as Joanne Sharp, was jailed for three years and seven months in February after admitting she stole more than $725,000 from the ministry.

"A warrant has been issued for the arrest of a 50-year-old New Zealand woman in relation to a fraud investigation," Victoria Police said in a statement on Saturday.

SCOTT BARBOUR/GETTY IMAGES Harrison was named as a fraud suspect at rural water corporation Goulburn-Murray Water in Victoria in 2011.

"Victoria Police is aware that the woman they would like to speak to is currently imprisoned in New Zealand."

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FAIRFAX NZ Labour's transport spokeswoman, Sue Moroney, says taxpayers deserve a full investigation into how the Transport Ministry handled the Harrison case.

An extradition treaty exists between New Zealand and Australia.

New Zealand police said any questions around the intention to extradite should be addressed to Victoria Police, as the New Zealand side's role is only to expedite any extradition request from another jurisdiction.

"That process would normally only take place at the end of any custodial sentence in New Zealand."

Harrison was named as a fraud suspect at rural water corporation Goulburn-Murray Water (GMW) in Victoria in 2011.

An Australian rural publication, the Weekly Times, said Harrison allegedly received tens of thousands of dollars in unjustified pay claims.

GMW said her case was referred to the Victoria Police Fraud Squad.

A source claimed Victoria Police raised concerns with a New Zealand travel agent, which in turn contacted the transport ministry, after Harrison booked ministry travel in 2013.

The Transport Ministry did not respond to that claim on Friday.

New allegations of wrongdoing by Harrison prompted fresh calls for an investigation into her activities, and into the treatment of whistleblowers at the ministry.

The ministry said on Friday that Harrison lied to a senior staffer while she was still a manager, after recommending her husband Patrick Sharp run a project at the Transport Accident Investigation Commission (TAIC).

Labour's transport spokeswoman Sue Moroney has called for a full investigation into how the Transport Ministry handled the case.

New Zealand First leader Winston Peters also called for further investigations into how whistleblowers who raised concerns about Harrison were treated.

While Harrison's crimes publicly came to light in July 2016, she was first questioned by the ministry - which had questions about contracts she was involved with - at least as far back as May 2014.

Harrison approached the TAIC about a ministry-funded proposal for apprentice investigators, which was initially rejected.

But when TAIC and the ministry agreed to advance a project already planned, Harrison provided funding and proposed her husband - Sharp - for the 12-month contract.

TAIC grew suspicious about the relationship between the pair, which was highlighted to the commission's senior management, who then brought it up with the ministry.

The Transport Ministry has confirmed Harrison lied to a senior manager there when asked if she was in a relationship with Sharp - claiming that she was not, and that there was no conflict of interest.

Documents released under the Official Information Act proved Harrison urged her former boss at the Transport Ministry, Martin Matthews, who is now the Auditor-General, to "close down" investigations when colleagues raised concerns.

He said in November he took "decisive and thorough" steps once learning of the discrepancies.

Police will not confirm or deny that they are investigating conflict of interest claims involving Harrison and Sharp.

A State Services Commission spokesman said on Friday the alleged conflict of interest over Harrison's recommendation of Sharp was an employment issue that the new Transport Ministry chief executive, Peter Mersi, had investigated.