Five venues named for Euro 2012
He said the Ukrainian cities of Lviv, Donetsk and Kharkiv would all have to prove their suitability by November 30 - adding that Warsaw could yet stage the final instead of Kiev if all of UEFA's pre-conditions were still not met by then.
"There are still many problems to be resolved in Ukraine. There are huge infrastructure problems," he told a news conference after UEFA's Executive Committee met in the Romanian capital.
"The final match will be held in Kiev only if specific conditions with regard to the stadium, airport infrastructure regional transport and accommodation are met by November 30," Platini said.
"Kiev is OK according to UEFA's criteria for all matches leading up to the semi-final. But certain other criteria must be met to stage the final as well. If it's not Kiev it could be Warsaw."
The Ukrainian city of Dnipropetrovsk, which was expected to be named as one of the four cities to host games was also dropped as a venue in place of Kharkiv, which was on the reserve list originally.
In a further slight to Ukraine, which has suffered more than most European countries in the global financial crisis, Platini said UEFA could proceed with four Polish cities and only two from co-hosts Ukraine.
"If the Ukrainian cities cannot fulfil the criteria by November 30 then we will organise Euro 2012 with four cities in Poland and two in Ukraine, and we will pick the second Ukraine city after Kiev from the best of the other three," he said.
Platini said progress had been made but a huge amount of work remained to be done in both countries.
"There are a lot of infrastructure problems that need to be resolved, especially in Ukraine, to convince the Executive Committee that the host city candidates can be appointed as host cities," he said.
He ruled out the tournament being staged anywhere other than Poland and Ukraine, but said the executive committee would closely monitor progress being made over the next six months.
Grigory Surkis, the president of the Ukraine FA and a member of the UEFA Executive Committee called for patience and understanding and said he was sure Kiev, which will stage group matches and a semi-final, would keep the final.
"UEFA have given us until Nov.30 to improve and I am sure we will," he said.
Preparations for the tournament have been blighted since the two countries were announced as co-hosts by UEFA in April 2007.
The tournament, the last to be contested by 16 teams before 24 finalists take part from 2016, is scheduled to begin on June 9 and end on July 1 2012.
It will be the third to be co-hosted after Belgium and the Netherlands staged Euro 2000 and Austria and Switzerland had the Euro 2008 competition, but the build-up to 2012 has been fraught