Ljubljana - Proponents of the referendum on the waters act have sharply criticised the organisation of the voting, alleging voter suppression regarding information on how and where people can vote early and polling station staffing. "We are faced with inadmissible curtailing of voting rights," Aljoša Petek of the Legal Information Centre said on Tuesday.

The statement comes after it was revealed that the Labour Ministry had dragged its feet on providing information to aged-care homes on how residents can vote, leading to protests by campaign organisers and the elderly.

The ministry has apologised and attributed the delay to human error.

As early voting started today, reports have been coming in about huge waiting lines at the sole polling station in Ljubljana dedicated to early voting.

In the past early voting was conducted at a dozen-odd polling stations in the capital, this year there is only one, a decision the National Electoral Commission says was prompted by the reorganisation of the Ljubljana Administrative Unit.

According to Petek, the National Electoral Commission had failed to secure sufficient staff for the poorly marked polling station, with people having to wait hours in the sun to cast their vote.

In Maribor, several people have reported being misinformed about the location of their polling station, according to Institute 8 March, one of the proponents of the referendum.

"We believe this is a mistake committed by the National Electoral Commission and that people's voting right has been curtailed as a result," said Marja Kodre of Institute 8 March.

The situation in Maribor is the exact opposite of Ljubljana, according to the regional daily Večer: where there used to be a single polling station for early voting, there are now seven.

Online, people could for some time today not register for one of the polling stations where those who vote outside their place resident can typically cast their ballots.

What is more, according to Kodre, there are problems with voting from abroad as the National Electoral Commission has used old records. The affected voters have been promised the situation will be resolved by Sunday.

There were also reports circulating on social media today of voters trying to cast their votes at their typical polling stations, only to be told that they in fact had to vote tens of kilometres away in a different administrative unit.

The National Electoral Commission said earlier today it was working with administrative units to resolve any outstanding issues.

Its president, Dušan Vučko, said the onus was on voters to check where exactly their polling station is.

Polling day for the referendum is this Sunday and early voting is taking place between Tuesday and Thursday.