Passengers have to disinfect their hands upon entry, wear a face mask and keep a safety distance of at least 1.5 metres to each other.

Buses are outfitted with special barriers for drivers and unless these are in place, passengers are not able to enter through the front door.

In Ljubljana, they are entering through the second door, where they are provided with a hand sanitiser dispenser. Tickets are validated at the validation port near the second door, and only by those with single-ride cards.

Bus passengers are not able to buy tickets on the bus. Ticket purchase are possible at bigger stops and stations, online and at ticket machines. The same is also advised by railways operator Slovenske Železnice.

The enforcement of the rules could prove a challenge, with Slovenske Železnice saying their staff will only be able to warn passengers that they need to wear masks, while only police have the power to take action.

The director of Ljubljana's public bus transport provider LPP Peter Horvat announced a more radical approach, saying drivers were instructed not to continue driving if they notice a passenger entering without a mask.

"The driver will notify the police or health inspectorate, let the other passengers off the bus and take the vehicle to the garage for disinfection, while we will sent a replacement bus," Horvat told the daily paper Dnevnik.

About every other seat on train is off limits, so as to ensure social distancing, Slovenske Železnice said on Friday, while a similar arrangement has been secured for buses.

At their last stop, the buses and trains will have to be aired out and disinfected.

Most public transport operators are planning a gradual restart, with Slovenske Železnice planning to dispatch only 30% of their coaches today.

International passenger transport remains suspended. Infrastructure Minister Jernej Vrtovec has previously mentioned 1 June as a possible date of relaunch.

Vrtovec told the TV Slovenija news show Dnevnik last night that passenger air transport may also be relaunched this week.

The minister symbolically reopened public transport today by taking the Domžale-Ljubljana train in the company of Slovenske Železnice director general Dušan Mes.

Mes said everything was running smoothly and that passenger numbers were modest so far in line with expectations. He said supplementary bus transport was planned if the number of passengers rises too quickly.

"Public transport is the backbone of our transport system, which is why I'm happy to see this day finally arriving. I want to thank the passengers for eight weeks of patience," Vrtovec told the press.

Very modest numbers are also reported by LPP, with Horvat citing for TV Slovenija a driver as telling him the atmosphere in the morning had been like at 4am on New Year's Day.

Horvat, who said he was in a way happy people remained careful, announced the number of active buses would be stepped up according to needs. A special challenge will be the gradual return of school children, who account for around 60% of LPP passengers.