Javier Solana made the announcement as European leaders began an emergency summit on the crisis in Brussels, reported dpa.
Divisions have emerged on how to react to Russia's military action, with the UK calling for a review of EU relations with Moscow and France urging dialogue.
Russia has warned further support for Georgia would be a "historic" mistake.
Speaking at the EU's headquarters, Mr Solana said he hoped its members would approve the plan to send monitors to Georgia over the coming weeks, and that they could be in place by mid-October.
"It will be a mission in the hundreds, not a huge one," he said, adding that no decisions on imposing sanctions on Russia would be taken at Monday's summit.
Earlier, the Russian foreign ministry said Moscow was ready to consider participating in an international police force in Georgia, allowing peace monitors in all areas of the country.
The EU already has some 40 observers on the ground in Georgia and diplomats say up to 200 could be deployed in the coming weeks.
The BBC's Oana Lungescu in Brussels says the summit is meant to send a signal of support for Georgia, but the EU remains deeply divided on how to respond to Russia's military interventions in the country's two breakaway regions - Abkhazia and South Ossetia.
Moscow formally recognised the independence of the two regions last week, in a move widely condemned by the West but which Russian President Dmitry Medvedev has said was irrevocable.
But calls for a fundamental change in the relationship with Russia are unlikely to get the support required, correspondents say, as many EU states are wary of alienating Russia, an important trading partner and a major energy supplier.
Monday's meeting is also expected to bring promises of substantial economic aid, a free trade agreement and easier travel arrangements for Georgians.
Ahead of the summit, UK Prime Minister Gordon Brown urged the EU to suspend talks on a long-delayed partnership agreement with Russia.
"In light of Russia's actions we should suspend negotiations on a successor to the partnership and co-operation agreement," his spokesman told reporters in London.
Mr Brown earlier called for a "root-and-branch review" of the EU's relationship with Russia, saying no nation should be allowed to exert an energy stranglehold over Europe.
But France, which currently holds the EU presidency and brokered the ceasefire agreement between Russia and Georgia last month, said Europe did not want to "recreate the Cold War".
By pointing the finger at Russia, we isolate it and continue to trample on it," Prime Minister Francois Fillon said. "This is not the way France has chosen. It's not the way Europe has chosen... and the word 'sanctions' is not on the agenda.
"The word on the agenda is 'dialogue', and I think the president of the French republic will put a certain number of initiatives to his European counterparts... that he will himself head for the capitals of Russia and Georgia again to promote the cause of peace."
Georgians hold up their flag at an anti-Russian protest at Trafalgar Square, London (1 September 2008)
Mr Fillon also denied accusations that Europe was "too indulgent" towards Russia, saying the attitude of the US government had hardly been more effective.
German Chancellor Angela Merkel also said the EU should not break off dialogue with Moscow but instead "speak clearly", echoing earlier comments by Foreign Minister Frank-Walter Steinmeier.
Georgians are holding rallies in Tbilisi and in other European capitals to coincide with the Brussels summit.
Thousands gathered at Tbilisi's Freedom Square, waving the Georgian flag and chanting "Long Live Georgia" and "Stop Russia".
President Mikhail Saakashvili told the crowd that Georgia was "united as never before" and urged EU leaders not to give up in the face of Russian "aggression".
"Today we can say that Georgia is not alone, because the whole world is standing beside us," he said. "Georgia will never stop resisting, Georgia will never surrender."
Earlier, Russia's Foreign Minister Sergei Lavrov warned the US and its allies that supporting President Saakashvili would be a historic mistake, and called for an arms embargo "while a different government turns Georgia into a normal state".
"To protect the region from the recurrence of violence, Russia will continue taking measures to punish the guilty, so that this regime is never able to do evil," he said.
Speaking in Moscow, Mr Lavrov said Russia had returned to the world stage as a responsible state which could defend its citizens.
Mr Lavrov's comments follow Mr Medvedev's redefining of Russia's foreign policy principles.
Russia, the Kremlin leader declared, would no longer accept a situation whereby a single country, like the US, sought global domination.
Mr Medvedev also pledged to defend the lives and dignity of Russian citizens, wherever they are located.
He made it clear that there were parts of the world where Russia sees itself as having privileged interests.
Russia's conflict with Georgia began on 7 August when Georgia tried to regain control of South Ossetia by force, and Russia counter-attacked deep into Georgia.