Labour remains committed to renewing the Trident nuclear weapons system, new shadow defence secretary Nia Griffith has said.
The issue of Trident has caused deep rifts within Labour as leader Jeremy Corbyn, a long-standing campaigner against nuclear weapons, does not agree with the party's official policy supporting renewal.
Ms Griffith admitted she had "in the past" had "serious doubts" about Trident but Labour policy was to back it and that was not likely to change.
She told Forces TV that Labour delegates at the party's conferences had backed the weapons system "and that is a commitment that we will stick to".
Ms Griffith added: "I don't see party policy changing any time soon because the votes have been quite consistent in conference."
The shadow defence secretary said Labour "can't be shilly-shallying about" on Trident, but added the UK must push for multilateral disarmament.
"What we do need to do now, and there is a very strong mood for this, both within the Labour Party and in the broader public, is really push forward on the multilateral nuclear disarmament, on the multilateral approach of bringing people together across the globe to try to make our world a safer place," she said.
Ms Griffith replaced Clive Lewis in the defence brief when Mr Corbyn reshuffled his top team after being re-elected as leader.
Mr Lewis was moved from the defence portfolio to become shadow business secretary following controversy at last month's Labour Party conference, when the leader's office doctored the ex-soldier's speech on Trident at the last minute.
Meanwhile, former Labour chief whip Dame Rosie Winterton, who was sacked in the reshuffle, has been made the party's envoy with responsibility for relations with Labour's international sister parties.
Announcing the appointment, Mr Corbyn said that she would take up Labour's vacancy on the Party of European Socialists.
The dismissal of the popular Dame Rosie angered many moderate Labour MPs and her new post is likely to been seen as little compensation.
Mr Corbyn said: "Rosie has a wealth of knowledge and experience and will be a real asset in helping the Labour Party develop closer links with our sister parties around the world."
The Labour leader also announced the appointment of seven more shadow ministers - taking his frontbench team to 68.
The new appointments are Paula Sherriff (women and equalities), Richard Burden (transport), Wayne David (defence), Khalid Mahmood (foreign office), Gill Furniss (steel, postal affairs and consumer protection), Rupa Huq (home affairs) and Lyn Brown (home affairs).
Gary Smith, Scottish regional secretary of the GMB union, welcomed Ms Griffith's comments.
"This is a sensible and inevitable climbdown," he said.
"There is no credible diversification plan for the tens of thousands of skilled jobs dependent on Trident."