The plan would see the marina's capacity doubled

But work on the development cannot start without permission from Dwyfor planning committee, which will consider a full application in September.

Pressure group Cymuned, worried about an impact on the Welsh language, called the board decision "unbelievable and irresponsible".

But others have argued that the expansion will bring jobs to the area.

Tuesday's board decision is the first major step forward for the plans, which had been delayed by the commissioning of reports into the impact on the local economy, the environment and the Welsh language.

'Mitigation'

The proposed expansion of Hafan Marina has proved controversial, with some local people and councillors questioning whether it would lead to an influx of non-Welsh speakers and a dilution of the language.

Geraint Hughes, a member of Cymuned on the Lleyn Peninsula, said: "Council officers and Plaid Cymru have recognised that there is a desperate need to mitigate the negative effects of this development, but there has not been a single statement about any specific plans - they clearly don't have any.

"The council has to state precisely what their intended mitigation plans are before the planning application is put in.

�1.5m has been proposed to ease the impact of the development

"I'm sure both sides would agree that there is no purpose committing to developments which will create less money than is needed to mitigate their damaging effects."

Pwllheli town councillor Ian Roberts said the scheme would bring jobs and benefit future generations.

Councillor Roberts said: "I support the development of Pwllheli marina for the simple reason that we owe the future generation something to look forward to. We owe them work at least.

"There are at least 30 young people learning skills with the marina in Pwllheli at the moment - these people are the future of the language.

"If they marry and have children and families, they are the future of the language. There's no doubt about it."

Whip

The development was proposed at the council meeting by development portfolio leader Dafydd Iwan, whose party - Plaid Cymru - made a last-minute decision to back the scheme on Monday night.

Twenty-two of Plaid's 28 Gwynedd Council members were believed to have initially rejected the proposals.

However, all but four are thought to have decided to support the expansion after an extra �1.5m to ease the impact of the development was proposed.

Some Plaid members had called for a whip to be imposed to force the vote against the development, however this was defeated by the compromise.

Mr Iwan said: "I would have been in a difficult position if there had been a whip since my name was on the report, I was the one putting it forward, and I would have had to at least abstain from voting.