Lerwick Port Authority has received a share of £1.8 million from the Scottish government towards safety improvement and repair work.
The money, £182,000, will go towards installing new lighting, a fish landing crane and an automatic weightbridge.
Fourteen ports and harbours were included in the extra support, said to be for “lost income for landing fees due to the disruption caused by Brexit”.
Other places to benefit were Peterhead, Fraserburgh, Scrabster, Ullapool, Eyemouth, Dunbar and Mallaig.
Scottish fishing minister Fergus Ewing announced details ahead of the third meeting of the Scottish Seafood Exports Taskforce where he called on the UK government to improve collaboration on border and customs process for the EU.
As a result of the botched Brexit deal and through no fault of their own, many are losing key landing fees from vessels and need this essential investment.
Mr Ewing said limited, complex guidance and the requirement to use multiple systems for catch and export certification and customs controls was leading to a number of EU vessels choosing to land into other countries like Norway, Denmark and Ireland.
EU flagged vessels accounted for around seven per cent of all landings by value into Scottish ports in 2019 and were worth £35.5 million, he said. However, there was more of a reliance on them in smaller communities.
Mr Ewing said: “Ports and harbours are the lifeblood of many of our coastal communities up and down the country.
“As a result of the botched Brexit deal and through no fault of their own, many are losing key landing fees from vessels and need this essential investment.
“Previously we committed £1 million but I am pleased to be able to increase this to £1.8 million so we can provide even more funding to approximately 20 ports and harbours and support jobs and livelihoods in our coastal communities.
“We’ve been working closely with the British Ports Association on this support and the ports and harbours will be able to start essential works immediately.”