Police deployed to flashpoints across the Mozambican capital of Maputo on Thursday, as a transport strike against bus fare hikes forced tens of thousands to cross the city on foot.

Shops, government ministries and banks in the city shuttered their doors fearing violence, amid protests against a local government-mandated fare increase of 40 percent.

An AFP reporter witnessed a heavy police presence across the city, as some mobile phone services were jammed to prevent protestors from organising.

The proposal to increase fares has prompted fears that violence seen after an attempted hike in 2008 will be repeated, when four people were killed during rioting.

Citizens in this overwhelmingly poor city complain they cannot shoulder the increased costs.

"The problem is our salaries have not gone up. The middle class is suffering," said state employee, Brigit Semedo.

Only a handful of private minibus taxis ignored a planned strike to ply their routes, making travel difficult. Two hours into a journey that normally takes one hour Semedo still had not reached her destination. "I may have to turn back," she said.

The ordinarily crowded terminal in central Maputo was all but empty, although municipal buses were running normally.

Many thousands took to the streets walking. The authorities say fare increases are the only way to revitalize a struggling transport system.

The city has only 250 public buses to carry around two million commuters, forcing many desperate travellers to jumping onto open-topped lorries to go to work.