Construction of the new Aberdeen Harbour is facing major delays, STV News can reveal.

The project is now due to be completed in 2021, a year behind the original estimation of August 2020.

The £350m expansion is the largest marine construction project currently under way in the UK.

When finished, the harbour will allow increased berthing for the oil and gas industry and provide a major boost for cruise ships.

Aberdeen Harbour Board said the project had encountered technical challenges associated with the South Breakwater as it entered the most demanding and complex phase of the works.

It said there would be an impact on cruise passengers with plans for South Harbour in 2020. However, North Harbour cruise operations will continue unaffected.

Michelle Handforth, chief executive of Aberdeen Harbour Board, said: "Aberdeen South Harbour is a visionary project, and one which will serve the region for hundreds of years to come.

"It is imperative, therefore, that we create a product of the highest quality, safety and durability.

"Any change in our programme is highly regrettable, but we're keeping our eye on the bigger picture, which is about creating a once-in-a-lifetime economic development opportunity for the region.

"We are still making excellent progress given the complexity of the project, and it is widely appreciated that infrastructure projects of this scale can be susceptible to technical challenges.

"We will keep working with our contractors and stakeholders to successfully manage these situations as they arise, and together we'll see this project through to a successful completion."

VisitAberdeenshire's chief executive Chris Foy: "We echo Aberdeen Harbour Board's comment that the South Harbour development will bring long-term benefits to the region, and we remain entirely confident that the resulting uplift in cruise traffic will drive increased tourism receipts into the region for many years to come.

"While it is regrettable that the revised schedule is likely to impact on additional excursions into the city and the shire during 2020, we are encouraged that the majority of scheduled vessels for 2020 will continue to call into Aberdeen using existing facilities.

"Their passengers will be the first to benefit from our new welcome volunteer programme, and we will continue to work with the Harbour Board, local businesses, city and regional stakeholders over the coming months so that logistics and expanded sightseeing programmes are good to go when the South Harbour is fully operational."