Labour has no problem with former MP Judith Tizard coming back to Parliament on its party list, leader Phil Goff says.

He was reacting to speculation that the party would select a non-list MP to stand in the Mt Albert by-election to avoid Ms Tizard returning to Parliament.

The by-election, expected to be held in June, will fill the seat left vacant by former prime minister Helen Clark who heads of to heat the UN Development Programme.

Helen Clark held the seat in last year's general election with a 10,350 majority but Labour only beat National by 2426 in the party vote.

National will try to seize the seat and the Greens have decided to stand a candidate which could split the left vote.

Labour list MP Phil Twyford, who lives in Kingsland in the electorate, has been identified as a front-runner for his party.

Some have speculated that Labour is developing a strategy to prevent Ms Tizard returning to Parliament.

Former finance minister Michael Cullen is also retiring and his list spot will be taken by Damien O'Connor.

If Mr Twyford then contested a by-election and won the Mt Albert seat he would cease to be a list MP and would be replaced by Ms Tizard who follows Mr O'Connor on the list.

But if an outsider was chosen and won the seat, Mr Twyford would stay as a list MP and there would not be a slot for Ms Tizard to take.

The Herald on Monday reported that Labour used UMR Research to hold focus groups meetings of Mt Albert voters. One question asked about Ms Tizard in terms of well-known people or celebrities standing for politics.

Mr Goff defended the use of focus groups saying they were a good way of getting a sense of local issues and how people would respond to particular candidates.

"I think what we want from Mt Albert actually is a local person, a person who can identify with the needs and aspirations of the people of Mt Albert," he told TV One's Breakfast programme.

He disagreed the expensive measures showed Labour was nervous.

"I'm not nervous about the outcome, I think we will win Mt Albert but we're not complacent about that."

Mr Goff said when a vacancy came up on the list it was automatically filled by the next person on it.

Asked how he felt about the potential return of Ms Tizard, who lost Auckland Central to National's Nicky Kaye, Mr Goff said: "I am very happy to see any former Labour colleague back in parliament.

"Judith Tizard is a very experienced member, very well respected particularly in the arts and culture community where she has worked so hard for so long."