This includes an additional freight service on Saturday evening.
The MV Isle of Lewis has been moved to the Stornoway-Ullapool route in the meantime.
The night service will commence on Saturday and continue until Wednesday April 21.
The news comes after a temporary suspension of a full freight service as the MV Loch Seaforth was removed from service due to a major technical issue.
However, CalMac has said it is engaging directly with the key business affected by the removal of the Loch Seaforth, and they are being kept updated about all developments.
A CalMac spokesperson said: “Work is ongoing to continue this timetable beyond Wednesday and this will be confirmed as soon as possible.”
“It is too early to speculate on the cause of the engine failure and a full investigation into the cause will also be carried out.
"While the possibility of temporarily hiring other vessels has been investigated, no suitable options are available for use at this time.”
Alternative connections are available via Uig-Tarbert.
Passengers for the Ullapool-Stornoway service are being advised to check service updates, CalMac social media channels, and the website for the latest advice.
Robert Morrison, operations director for CalMacsaid: “Getting freight moving to and from the island has been a priority since the Loch Seaforth was taken out of service, and we have been working non-stop to find a solution.