Marjan LMŠ, the runner up in the 3 June early election, also said that it was drafting a coalition agreement which would serve as the basis for future talks.
It explained that today's meeting was meant for the parties to agree on the form of their future meetings.
It was attended by secretaries general of five centre-left parties - the LMŠ, Social Democrats (SD), Modern Centre Party (SMC), Alenka Bratušek Party (SAB) and Pensioners' Party (DeSUS) - plus centre-right New Slovenia (NSi).
However, it is not known how talks on bringing different platforms closer together will proceed, or whether representatives of all six parties will meet again this week.
Meanwhile, Janša said the time for coalition agreements was after President Borut Pahor decides on the prime minister-designate.
Speaking to the press after a meeting of parliamentary parties with PM Miro Cerar, he said the SDS had already talked to other parties, but did not specify with which.
"But the truth is that only the NSi came to the meeting with open questions, it knew what is written in our platform and we knew what is written in their's, which things we have in common and where there are differences."
This first round of talks is, according to Janša, testing the parties' readiness to sign a coalition agreement and whether they have staff for this government term, during which Slovenia will also preside over the European Council.
Only after this has been established can the talks move to the next stage when concrete harmonisation of different views takes place, explained Janša.
The SDS has a draft coalition agreement ready alongside 14 negotiators with teams to enter coalition talks, so he said they could complete the whole process very quickly.
Commenting on today's LMŠ-sponsored meeting, Janša said all talks were useful.
"It is good if some dilemmas are solved before formal talks get under way, because the process will then unfold faster.
"If it is established that somebody else rather than us as the election winners can form a majority, then we won't be bothered with it. So no talks are undue," Janša told the press.