Scotland said it will act to keep more offshore wind contracts within its borders through compulsory “supply-chain commitments” with project developers, after stinging criticism over the number of deals and jobs vanishing abroad.

The Scottish government announced the plan after a sector summit in Edinburgh called to discuss the issue following a backlash from companies and unions, which have branded the situation a “scandal”.

A statement said developers will have to agree supply chain commitments when applying for leases – Scotland is due to kick-off a major new leasing round this year.

Scottish economy secretary Derek Mackay said: “Scotland is the ideal location for offshore wind, but recent projects have not delivered the significant economic opportunities we want to see for Scottish businesses.

“The Scottish Government has been calling for the offshore sector to do more by awarding contracts to our indigenous supply chain but recent disappointments suggest that more has to be done.”

Crown Estate Scotland – which will run the ScotWind leasing round, and took part in the summit with industry and government representatives – said the initiative would involve developers seeking seabed rights “laying out the anticipated level and location of supply chain impact from each phase of their proposed project. These commitments will then be formally incorporated in to each ScotWind agreement and updated throughout the project development as plans become more defined.”

The seabed landlord added: “As these aspects will be part of the agreement process, there will be contractual consequences if supply chain commitments are not delivered.”

Supply chain plans specifying proposals for local content are already part of the process at UK level for applying for a contract-for-difference (CfD) deal via government auctions.

The level of local content and jobs generated by the 448MW Neart Na Gaoithe being built by EDF off Scotland has proved a particular flashpoint for criticism

Another recent flare-up came in October last year when union Unite reacted angrily to news that tower-maker CS wind planned to lay off three quarters of its workforce at its factory in Campbeltown.

Unite and fellow union GMB welcomed the “long overdue” new measures, but added: “In 2011 employment in Scotland’s offshore wind sector was forecast to be 28,000 direct jobs and 20,000 indirect jobs by 2020. We are nowhere near that and in the last few months redundancy notices have been handed out at supply chain firms like BiFab and CS Wind.

“In the same period, industry majors like SSE have been subsidised to the tune of billions of pounds of public money through the UK government’s CfD scheme, with no link at all to domestic job creation commitments.

“It’s a scandalous story of missed opportunities and ultimately one of industrial and political failure.”

The unions added: “Without a detailed industrial plan involving the industry and a substantial programme of investment for our supply chain, our green jobs revolution will continue to be delivered in Spain, Saudi Arabia, UAE, Indonesia and China – anywhere but Scotland.”

Note: Update adds quotes from Unite and Crown Estate