Portsmouth City Council, which owns the building, has applied for listed building consent for work on its eastern side, including 'careful' dismantling and rebuild of the parapets.
A heritage report submitted with the application says the works are needed to maintain the integrity of the structure and also include upgrades to improve ventilation.
'The Kings Theatre is an important heritage asset as summarised above and is significant for a number of reasons,' it says. 'The theatre is extremely important to the local community in Southsea and in the surrounding area.'
Alongside the reconstruction of the parapets, the plans include rebuilding the brickwork buttress cap, repointing, wall repairs and repairs to windows along the eastern side of the building, including those which have been boarded up.
Drainage improvements, re-roofing and the installation of mechanical ventilation systems for the toilets and the Matcham Bar are aimed at reducing damage to the structure of the building.
The council is also proposing to replace the theatre's boilers.
A target date of April 19 has been set for the council to reach a decision on whether to approve the works.