LABOR'S "captain's pick'' Senate candidate Nova Peris said she would have crossed the floor to oppose the Muckaty nuclear waste dump - and would vote against her party if she felt strongly about other issues.

Ms Peris said the Muckaty nuclear waste dump - planned to be built near Tennant Creek - was one area where she would go against Labor Party policy.

"I met with the anti-nuclear campaign people and I also met with the NT environment mob, and I have met with the Tennant Creek residents, I have met with the unions and I have met with three of the traditional owner groups,'' Ms Peris told the NT News.

"In my view I do stand with them in opposing that (nuclear dump).''

The Muckaty nuclear waste dump has been planned to be built near Tennant Creek and has been supported by both Labor and the Coalition.

Some traditional owners from Muckaty are fighting the decision to have the dump located at the site, and the issue is being decided by the Federal Court.

Legislation enabling the Muckaty nuclear waste facility has been passed by the parliament, but Ms Peris said she would have crossed the floor to vote against it.

Ms Peris added that on exceptional issues where there was a clear message coming from the people of the NT that was different to that decided by the ALP caucus she would side with the people of the Territory.

Asked if she would cross the floor on issues she felt passionate about she said: "If I felt passionate and that was the right way to do it, then yes.''

If elected to the senate she would not be speaking for herself, but on behalf of Territorians, she said.

"I speak for them once they tell me what they want me to say,'' she said.

"For me having a voice in parliament, it is not my own voice, it is the voice of the people.''

Federal Indigenous Health Minister Warren Snowdon, who was travelling with Ms Peris on a trip where she made the comments, said once a decision had been made by caucus Labor politicians must vote for it.

"She will have difficulty getting that across, I can tell you,'' Mr Snowdon said.

"If you have a free-for-all where you are there wearing the Labor badge and you don't like a particular set of decisions and you vote against it, that is instability and we don't want that.

"There is no flexibility on whether people can cross the floor or not.''

Ms Peris was named by Julia Gillard as a "captain's pick'' to be the ALP's top choice to be a senator in the NT.

The move was later endorsed by the ALP National Executive, meaning Ms Peris's election to the Senate is all but guaranteed.