Foreign Secretary William Hague says he has not ruled out sending weapons to Syrian opposition groups in the future.
Britain has supplied communications equipment but not weapons to rebels, the Foreign Affairs committee was told.
Mr Hague dismissed suggestions the UK was trying to arm groups by the back door by "outsourcing" the job to nations such as Turkey and Saudi Arabia.
"We are not paying any other country to do that," he told MPs.
Asked if the UK or Nato partners should intervene to stop other nations arming groups in Syria Mr Hague said: "This is the argument that we would need to intervene ourselves or to send lethal weapons in order to prevent other people from doing so.
"First of all I don't think that would necessarily prevent anybody else from doing so. Secondly there are major other drawbacks to that policy. We wouldn't necessarily know how those weapons were used and the conflict in Syria could increasingly be defined as one in which the West is intervening and there would be major disadvantages to that, including for people in Syria.
"I think the drawbacks for such a policy as things stand today - I don't rule out any option in the future because we don't know how the situation will develop - outweigh the advantages."
Mr Hague, who is holding talks with senior Russian figures next week, warned the situation in Syria is "deteriorating" and vowed to continue pressing Russia to back tougher action against the Assad regime.
The Foreign Secretary also condemned the makers of a film mocking Islam that has sparked unrest across the Middle East, saying it was a "contemptible" piece of work.
He told the committee he had called US secretary of state Hillary Clinton to discuss security arrangements over the weekend following the killing of America's ambassador in Libya. The US embassy was stormed by a gang of armed men following the uproar over the US film.