Former Alliance president and leader Jill Ovens has relinquished her Alliance membership altogether to join Labour after her election as northern secretary of the Labour-affiliated Service and Food Workers' Union.

She said she made the decision because many members of the union had wanted her to join Labour.

Contrary to what opponents had suggested in the campaign for the post, she had no wish to see the union disaffiliate from Labour.

"It wasn't a big issue for me but it was a big issue for my members."

In an upset vote by 122 delegates, Jill Ovens won the vote in June after a vacancy created by Darien Fenton's appointment as a Labour list MP.

Jill Ovens had been an organiser with the union for just 18 months and Darien Fenton's preference had been rival Lisa Eldret.

With 10,000 members, the Northern Service Workers' Union comprises almost half of the National Service Workers membership and many are based in the important Labour stronghold of South Auckland.

Jill Ovens said she had sought out Labour insiders early in the campaign to reassure them there was no danger of the union disaffiliating under her secretaryship.

"I have no intention of disaffiliating from Labour. I actually think it's quite important for our union to have a close relationship with Labour."

She said she hoped a leaked email in which she referred to Labour apparatchiks as "dogs" would not affect her membership bid.

In the email - to former Alliance colleagues - she had been trying to distinguish between Labour people who had attacked her during her campaign to become secretary and ordinary working people who believed in Labour.

Labour's union affiliates council secretary, Paul Tolich, said last night that her "more intemperate outbursts" would have no bearing on her application, which had been approved.

Asked if Jill Ovens might follow others who have held the post - Rick Barker, Mark Gosche and Darien Fenton - into Labour's caucus, Mr Tolich said, "I wouldn't know".

Jill Ovens was part of the ultra leftist wing of the Alliance. She has twice stood against Helen Clark in Mt Albert, in 1999 and 2002.

She sought to keep the party going after former leaders Laila Harre and Matt McCarten left.

The three are now in leading union posts: Matt McCarten is head of the low-paid workers union Unite, Laila Harre ousted veteran unionist Mike Jackson to take over the National Distribution Union and Jill Ovens has a pivotal role with the Service Workers.