Taxis and mini buses have blocked an access road leading to the airport and traffic is being diverted through other roads.
The disruption is the latest in a series carried out by transport workers who are on strike in protest over liberalisation.
Traffic to the airport near the DHL roundabout in Luqa has been ebbing and flowing for the past hour, with some of the lanes being opened by the police, only to be closed again by the strikers.
Traffic has meanwhile started to flow out of Valletta through St Anne Street, Floriana after mini buses at about 5 p.m. lifted a 'blockade' lasting several hours.
Traffic in the busy street was also reduced to a snail's pace twice in the morning as buses, taxis, hearses and mini-buses blocked lanes or drove very slowly in the morning. Other traffic disruption was caused in St Julians, Marsa, the Sta Venera Tunnels and the Regional Road.
A Net Television cameraman was slightly injured when he was punched while covering the disruption caused by the public transport strike this afternoon. The incident happened in Floriana.
A private van carrying tourists also had its windscreen smashed in an incident near the War Memorial in Floriana. No one was seriously injured.
The transport workers held a noisy protest outside the Auberge de Castille shortly before noon, and there were scuffles with the police when they rushed the main door, which was hurriedly closed. The drivers were eventually pushed back and no one was injured (see separate report).
Transport Federation president Victor Spiteri later told the workers that their industrial action would continue, and they would hold another protest outside Castille if their message does not reach the government.
Mr Spiteri, said that the strike ordered by the federation was successful, with all members taking part.
He said that while the members had not wished to interrupt rush-hour traffic, they were holding protests in different parts of Malta to press their point.
Some of the mini-buses and buses are carrying streamers reading Flimkien Kollox Possibli, the PN election slogan.
The indefinite strike was called to protest over the liberalisation of licences for the operation of hearses.
The federation has said it will not call off the action until new licences are withdrawn. The government cancelled a previously agreed meeting with the federation and said the decision on the hearses is final.