Seven Foreign Affairs Committee members visited the detention centre for "enemy combatants" in Cuba in September.
In a report they were critical of the conditions there, but said many inmates posed a threat and the world needed to find a "longer term solution".
Opposition MPs and human rights groups called the report "disappointing".
'Real threat'
The Guantanamo Bay facility was set up at a US base in Cuba after the invasion of Afghanistan in 2002.
A total of 395 prisoners are currently being held there, including 10 British residents, whom the government says it is not obliged to try to bring home.
According to Clara Gutteridge of human rights group Reprieve, these 10 are of non-UK nationalities but with "long and serious ties with this country or who have indefinite leave to remain in the UK".
The report by the seven MPs said many of those detained presented a "real threat to public safety", and said all states were under an obligation to protect their citizens and others.
But at present only the US was doing so, and "the international community as a whole needs to shoulder its responsibility in finding a longer-term solution," it said.
The chairman of the committee, Mike Gapes, told BBC News: "The problem is if you closed it straight away what do you do with the people that are there?
"Some of them no doubt could be released - sent back to their country of origin and be of no threat to anyone. But there are people there that are dangerous people...
"The international community as a whole needs to look at finding a longer-term solution."
24-hour lighting
The MPs spent only one day at the camp and had no direct access to detainees.
Their report says food was plentiful, medical care good and the facilities broadly comparable with a British maximum security prison.
But they said the camp did not meet UK guidelines for recreation and education facilities nor for access to the media, lawyers and the outside world.
The report adds that most inmates are confined to small cells with little contact with the other prisoners and few opportunities to exercise.
One area apparently was closed for repair after detainees had been found dismantling the plumbing to make weapons.
Electric lighting was kept on 24 hours a day. Some detainees were reported to be clinically obese; two were being force-fed and 20% had some psychiatric condition.
The MPs said prisoner abuse had "almost certainly" happened there but the added that this was "unlikely to be taking place now".
And they said the government was right to "stick to its established policy of not accepting consular responsibility for non-British nationals".
'Missed opportunity'
Liberal Democrat MP Sarah Teather, who represents a 10-year-old constituent whose father is being held at the camp, said the committee appeared to have been given "the VIP antiseptic tour".
The camp once held 750 inmates, including several British citizens.
"The committee were given no direct access to prisoners, and they do not appear to have taken evidence either from former detainees, or lawyers or families of current detainees," she said.
Tory MP Andrew Tyrie, who chairs the all party Parliamentary group on extraordinary rendition, said the report did not address the main issue, "which is whether US detention policy, whether in Guantanamo or elsewhere, is making the US, UK and the West more secure or less".
Amnesty International said the report was a "missed opportunity".
"We would have liked to have seen the committee unequivocally backing Amnesty International's long-standing call for Guantanamo to be closed immediately," said the organisation's UK director Kate Allen.
"We do not share the committee's apparent confidence that abuse is unlikely to be taking place now," she added.
Clive Stafford Smith, legal director of charity Reprieve which represents 38 prisoners at the base, said the report was "full of factual errors" and largely based on a "show tour".
Source: BBC
