Regional Development Minister Simon Crean has moved to amend the Self Government Act.
The changes would give MLAs power over their numbers.
Currently only the Federal Government can change the numbers in the 17 member assembly.
"This bill does not change the size of the assembly. It simply amends the mechanism by which the size of the assembly can be changed by removing the Commonwealth's role in the process of approving amendments in the size of the assembly," Mr Crean said.
"This bill acknowledges the capacity of the ACT to run its own affairs and provide it the power to determine the number of members it requires to do so in the Legislative Assembly."
Chief Minister Katy Gallagher says she is pleased the Commonwealth has responded to her request.
"An increase to the size of the assembly will still require a 2/3 majority and remains the ACT Government's preferred approach to ensure that there is bipartisan support for any change to the assembly's size," she said.
Late last year Ms Gallagher commissioned an expert panel to review the size of the assembly, which is due to report at the end of March.
"I hope that the Federal Parliament is now able to see the amendments passed prior to the Federal Election in September," Ms Gallagher said.