The Greens have announced the formation of a new national council in a move that aims to professionalise the party and revamp its stagnating support base.

The 25-person council will be made up of representatives from the party room, state and territory branches and office bearers. It will meet 10 times a year to streamline policy-making and campaigning, processes that are encumbered by varied ad hoc party groups.

Head of the party, Christine Milne, has described the council as a “very exciting thing that will professionalise how we work and make us much quicker and more effective”.

“When I took on the leadership, it was clear to me that it was important to move to a cabinet-style structure,” Milne told Guardian Australia. “There wasn’t resistance. People had become accustomed to the old ways of doing things, but there is an overwhelming appetite for reform [within the party].”

Milne had previously signalled that an overhaul of the party’s constitution was needed in order to win more seats.

“We’re now in a really good position to grow even further,” Milne said in announcing the reforms, acknowledging that the party’s complicated existing structure makes it difficult for rank and file members to have their say.

But a political scientist at Monash University, Zareh Ghazarian, warned that the council must not alienate the rank and file or it will face internal instability and even a split within the party. He said there is often a schism between what the politicians want and what the party members want, and the council must listen to grassroots members.

“That is a potentially very dangerous situation,” he said. “The appeal of the Greens is the reliance of ordinary members in policy making.”

Ghazarian said the reforms would make the Greens a “much more mainstream party in terms of their structure”, noting that it can no longer rely on the personality and political presence of its founder, Bob Brown, to hold the party together.

Brown was a federal senator from 1996 to 2012, after representing the Greens on a state level in Tasmania since 1983.

The Greens have 10 representatives in the Senate, and one in the lower house, despite mixed fortunes in the 2013 election when its primary vote fell. It must also contend with a number of other Senate crossbenchers, whose combined numbers mean it no longer holds the bargaining chips.

The Senate crossbenchers comprise three Palmer United senators, Liberal Democrat David Leyonhjelm, Ricky Muir from the Motoring Enthusiasts’ Party, Family First’s Bob Day and independents John Madigan and Nick Xenophon.

“Everybody has shared balance of power now,” Milne said.

Ghazarian thinks that the Greens are a “significant political force”, regardless of plateauing public support which hovers around 10% in federal seats, down from an all-time high of nearly 14% in the 2010 federal election.

“It’s easy to dance on the grave of the Greens even though they are yet to die,” Ghazarian said. “They are still capable of holding the balance of power.”