Sarah Dowie's political career all but over after Jami-Lee Ross scandal

Sarah Dowie's short-lived political career looks all but over.

The Invercargill MP from 2014 is almost certain not to be a National Party candidate in the 2020 election - assuming she does not resign beforehand.

One of the worst-kept secrets in politics was revealed yesterday, when the Herald confirmed police were investigating a text message, allegedly sent from the phone of Dowie, to former National MP Jami-Lee Ross.

The text message, which included the words "You deserve to die", was sent in the wake of the end of an extra-marital relationship between the two MPs. Well-informed sources said the affair had caused turmoil in National party circles in Invercargill.

Several members of Dowie's electorate committee had resigned in recent months.

It is understood several members of Dowie's staff have also resigned.

She is advertising for staff to work in her Wellington office.

Dowie was not answering her mobile phone yesterday or responding to a text message requesting comment.

The doors were locked and the lights off at her first-floor office in Kelvin St, Invercargill.

On one of the doors was a sign informing visitors that the office was closed for the festive season and would only open on January 28.

Ross and Dowie were understood to have been in a relationship for more than two years. It is believed to have ended about May.

National electorate candidates are selected by the electorate committee, with input from the party board and regional council.

Candidates are required to "exhibit the skills, experience and commitment to the party values and policies to make them suitable for candidate selection" - a test sources suggested Dowie would now be regarded as most unlikely to pass.

National's leadership was hardly rallying around to support Dowie yesterday, refusing to comment on the issue.

Dowie is the daughter of two police officers. It is understood she is separated from her husband, former Otago cricketer Mark Billcliff. They have two children.