SA marine sanctuary zones to stay

South Australian independent MP Geoff Brock has voted down a controversial Liberal Party push to water down the state's marine sanctuary zones.

The Regional Development and Local Government minister's vote gave the government a 21-20 victory on Thursday in the House of Assembly.

The Liberals had sought to exclude some areas from becoming marine sanctuary zones in October.

The former Liberal Party leader and now independent Martin Hamilton-Smith supported the amendment, which had been passed by the upper house.

In 2012, the Labor government set up a network of 19 marine parks that places restrictions on commercial and recreational fishing.

The parks also include smaller sanctuary zones, which will essentially become no-go areas for fishing in October.

Opposition Leader Steven Marshall said the vote would cost jobs in regional areas.

"It is disappointing that Minister Brock - who is supposed to be representing regional South Australians - has abandoned regional South Australians by voting against this bill," he said.

Mr Marshall said Mr Brock had gone against the wishes of councils, noting the zones had been widely condemned by the fishing industry, recreational fishers and regional communities.

But conservation groups say the result was a win for regional communities, fish stocks and marine life.

"After 15 years in the planning and over $40 million of investment, it's a huge relief to know that South Australia will finally receive a great marine parks network in less than a fortnight's time," Wilderness Society SA director Peter Owen said.

Conservation Council of SA chief executive Craig Wilkins said SA would be able to market the state to the world as a place to experience nature at its wildest.

"An increasing number of tourists pay a lot of money to experience whales, dolphins, seals and sharks and South Australia is one of the best places in the world to experience all of these natural wonders," he said.