The Great Hall in which the National Assembly sits was renovated in 2000 (from August to December). The renovation was designed by architects Sonja Miculinić, Albina Kindlhofer and Darja Valič.

The colour combinations and choice of materials (grey flooring and grey granite from Pohorje on the floor, white walls and ceiling, cherry veneer on the walls and deputies’ desks, and grey leather deputy chairs and balcony chairs) give the space elegance, lightness, and harmony. The wall behind the seats of the National Assembly's presidency is marble from Hotavlje.

The Great Hall is circular and measures 422 m² in area. The circle, featuring granite flooring in the centre, characterises the centre of legislative power, the seat of the highest democratic institution. The circular design corresponds to the Slovenian archetype of elders gathered in a circle at a stone table under the village linden tree. The stone central circle is associated with the symbolism of the Prince's Stone and follows Jože Plečnik's idea who in 1947 drew up a design of the Slovenian parliament in the form of a cone with a circular base (the unrealised project of the Cathedral of Freedom).

The circular design of the area is based on an idea by architect Jože Plečnik. The democratic circle of community emphasises the area where discussions, arrangements and decisions take place.

The Great Hall has seating for 150 people. It is circular and in the form of an amphitheatre sloping down to the semi-rotating podium. Each deputy seat is equipped with a microphone, a voting system with identification card, an interpreting system, power plug and access to the National Assembly's computer network. Chairs are rotatable, moveable and can be adjusted for height.

The chairs overlooking the main entrance to the hall are the seats of the President of the National Assembly and the Government. The position of the President of the National Assembly is equipped with central voting equipment and a screen. On the marble wall behind the President is a bronze relief of the Slovene state coat-of-arms, a work by sculptor Marko Pogačnik. It was made to celebrate Slovenia's independence in 1991.

The walls of the Great Hall feature three plasma displays. During sessions, they indicate the time allotted for discussion to deputies, deputy groups and the Government, the deputies present at voting and the voting results, as well as other information as needed.

The balcony or the gallery overlooking the Great Hall is primarily intended for the public, but also for the diplomatic corps and invited guests. The gallery has 106 seats covered in dark grey leather and arranged in four rows. There are four interpreter booths in the gallery which are also available to radio and TV reporters during live broadcasts of National Assembly sessions.

The central area in the lobby of the gallery serves as an exhibition space where protocol gifts are on display.

The Small Hall in which the National Council holds meetings is located on the ground floor of the parliamentary building on Šubičeva Street. The Small Hall is also used by the National Assembly for conferences, training seminars and public presentations of opinions organised by the National Assembly's working bodies.

The Small Hall, renovated in 2019, is home to the National Council. It is also used to publicly present opinions, hold seminars, consultations, and conferences, for educational purposes, and as a venue for other events. The hall used to seat 120, but the renovation brought its seating capacity down to 90. It can also serve as a spare hall for National Assembly sessions.

The renovated Small Hall continues to slope down towards the table of the president and is flanked by balconies on both sides. The work preserved the venue’s tendency to eschew sharp edges, as well as the hall’s other unique features: the conservation and restauration work undertaken on the hall sought to preserve its wooden elements as much as possible – the ash-wood panels and doors, the cornices, and the pear-wood fluted vertical cladding next to the windows. The new tables are covered with oak veneer, while the seats are made from white leather. The hall also boasts a new conference and voting system, television cameras, and displays.

The renovated hall incorporates three motifs: the ear of grain, its ripening, and the chaff riddle. The round openings in the hall ceiling represent a “sieve and riddle”, the National Council, which functions as a corrective mechanism, itself symbolically sifting laws passed by the National Assembly.

The lobby leading into the Small Hall can host receptions, exhibitions, and other events, as well as be used to give statements. The lobby features restored ash-wood panelling and walnut doors; the new cloakroom counter is made of oak and the two renovated niches are covered with grey-dyed veneer. The floors are newly tiled with grey-pink Cordevolian limestone from Hotavlje.
 

The meeting and reception rooms used by the National Assembly's working bodies and services are situated in the building on Šubičeva Street 4 (reception rooms 113 and 112 intended for protocol visits, and meeting rooms 110, 209, 212 and 217).

Two other halls (one large and one small) are located on the ground floor of Tomšičeva Street 5, from which the Slovenian national television usually broadcasts live meetings of working bodies.

A sound-isolated room is situated in the basement of Tomšičeva Street 5 which is intended for closed sessions or for the discussion of documents classified as confidential, secret or top secret under the Classified Information Act.