Trident is a submarine-launched ballistic missile system
The UK's decision to renew its Trident nuclear deterrent is seen by some foreign states as a contradiction of its non-proliferation stance, MPs say.
The Commons foreign affairs committee urged the government to "intensify its public diplomacy work... to explain the reasons for the renewal decision".
However, the MPs went on to praise the UK's arms control record as the best of the five global nuclear powers.
CND welcomed the report, but renewed its call not to replace Trident.
The cross-party committee said it welcomed an announcement by the UK government that the new Trident submarines would carry fewer warheads than the current vessels.
But it said the government should do more to highlight this and other nuclear disarmament steps it has taken.
The committee said the decision to renew the Trident system "is perceived by some foreign states and some among the British public as appearing to contradict the government's declared commitment to strengthening the international nuclear non-proliferation regime.
"We recommend that the government should intensify its public diplomacy work better to explain the reasons for the Trident renewal decision and to give greater prominence to its work for multilateral nuclear disarmament and arms control."
The UK's record on disarmament was often viewed alongside those of the four other nuclear powers - the US, Russia, China and France, according to committee chairman Mike Gapes.
He said: "The five recognised nuclear powers are often perceived as a group by the non-nuclear weapons states,... as such, the group is seen collectively to have failed to live up to its nuclear disarmament commitments."
Kate Hudson, chair of the Campaign for Nuclear Disarmament (CND), said she welcomed the foreign affairs committee's report.
She said she had "significant concerns" that pushing ahead with the decision to renew the government's Trident nuclear deterrent sent a "contradictory message" to its non-proliferation stance.
"The government should put its money where its mouth is and not go ahead with the Trident," she said.
But she said she welcomed the committee's recommendation that further debate was needed.
The committee said North Korea and Iran continued to pose a critical threat to international peace and stability.
Their actions are among the issues that will be considered at the Nuclear Non-Proliferation Treaty Review Conference next year.
The MPs said nuclear disarmament talks which were relaunched recently by the US and Russian presidents "could greatly aid progress at the 2010 conference".
The report also said that American plans for a missile shield in the Czech Republic and Poland should only be developed, if at all, as a joint system with Nato and Russia.