Daytime sailings are an option currently being considered by ferry bosses in response to concerns over capacity on NorthLink boats.
Transport Scotland said it is currently exploring the idea with operator Serco NorthLink Ferries and will report back in due course.
It comes after councillor Ryan Thomson raised the idea directly with the Scottish Government agency, which contracts Serco to run the Northern Isles service.
Capacity on the boats has been a consistent issue over the years, but this summer has things brought back into sharp focus.
Writing in response to Thomson, Fiona Lucas from Transport Scotland’s ferries unit said: “An update will be provided to stakeholders when all of the details are available, and we are able to consider fully the effects this proposal would have on the ferry service.”
She added that the government “fully recognises the key role” the Northern Isles ferry service plays in supporting the economic, social and cultural development of Shetland and Orkney, and the “critical importance of these services to those who live and work on the islands”.
Lucas said she hoped the response assured Thomson that “we are considering all available options”.
At the moment the two passenger ferries spend the day in port in Lerwick and Aberdeen after their overnight sailings.
Thomson, a former transport chair in the council, said he felt it was worth exploring the idea of introducing a combination of daytime and overnight sailings.
His proposal is for three daytime sailings and four evening trips a week all year round, with additional journeys laid on in the busier summer months as necessary.
Thomson said he was encouraged that there “appears to be a change of stance at Transport Scotland when it comes to changing the current timetable to a mix of daytime and overnight sailings.”
“A mix of daytime and overnight sailings would give islanders a choice of when they travel, assist in the cabin capacity issues and save travellers money if they choose to travel during the daytime without the need for a cabin,” he added
“I look forward to hearing the conclusion of the investigation and discussions with Serco, and that our lifeline service returns to a service which puts the passenger, and the islander as priority.”