Bulbs have been failing at an increasing rate and the type of light used is about to be banned by the European Union.
Officials say the lighting system is coming to the end of its natural life, 12 years after the Holyrood building opened.
They fear that if action is not taken, the lights could fail and business in the chamber would have to be cancelled because it could no longer be broadcast.
The Scottish Parliamentary Corporate Body (SPCB) – the cross-party group of MSPs which oversees the building – has discussed the problem and received a presentation on the options available. It is understood they have accepted there is little alternative but to fork out for a new lighting system, although no formal decision has yet been taken.
One parliament source said: “The lights in the chamber started to fail at a high rate – it had been two or three a year, but last year it was about 30.
“The EU rules are about to change which will make our system obsolete. In two or three years it will be impossible to replace the lights. The idea is to go for a replacement system with a 25-year lifespan.”
It is understood the current lights are metal halide lamps which are due to be phased out from the EU from next year on energy efficiency grounds.
And Brexit will make no difference because there is said to be only one manufacturer, based in Germany, who will almost certainly cease production when the ban comes in.
A source confirmed the cost of a new system was expected to be just over £1 million.
The parliament building was officially opened in 2004 at a final cost of £414 million.
In 2011, the parliament said MSPs’ voting consoles and microphones in the chamber had reached the end of their useful life and a new touchscreen version was installed with a bill for £280,000.
Last year the parliament spent £500,000 on upgrading the lighting in the main public foyer after complaints that the original design by architect Enric Miralles – deliberately intended to create a “subterranean” feel – made the entrance too dark.
Lothian Tory MSP Miles Briggs said: “People will be deeply concerned and annoyed at the vast cost of replacing these lights and will want to be reassured that all other options have been thoroughly considered before this work goes ahead. Given the pressure on expenditure across all parts of the public sector, it is vital that the Scottish Parliament demonstrates it is offering the taxpayer the very best possible value for money.”
A Scottish Parliament spokesman said he could not comment on the budget for the replacement of the lights.
But he said: “The chamber lighting system is approaching the end of its working life. The SPCB is therefore considering its options on whether to replace the lighting system.”