Premier Jay Weatherill pledged a re-elected Labor government would give $150 million to a new port authority to develop a deep-water port in regional South Australia.

The funds will allow the authority to borrow more than $500 million for the port to be built on Eyre Peninsula, giving a boost to the agriculture and mining industries.

"The flow-on benefits will be extraordinary for the whole state," Mr Weatherill told reports on Saturday.

The move was welcomed by the state's grain farmers and mining sectors who have warned of pressures on infrastructure due to growth.

"Currently, a third of South Australia's exports are generated by the resource sector, we have an impending bottleneck," SA Chamber of Mines and Energy chief executive Rebecca Knol said.

Opposition spokesman Corey Wingard said the idea of a port may have merit but Labor could not be trusted to deliver it.

"After sixteen years Labor has talked about ports on and off ad nauseam and they haven't delivered, it is all talk," Mr Wingard said.

His party was courting young families on Saturday, pledging the Liberals would spend an extra $12 million dollars on sports vouchers for primary school children.

They will increase the vouchers, available to all families, from $50 to $100 to help ease the rising cost of equipment and registration fees.

"This will help relieve the cost of playing sport and more importantly keep young people active," Mr Wingard said.

Meanwhile, Nick Xenophon announced SA-BEST's coastal protection policy pledging to set up a new authority to protect Adelaide's beaches from erosion and other environmental issues.

"Dealing with seagrass, dealing with stormwater going into the gulf, all these things will make a big difference for a long-term solution," Mr Xenophon said.

The former senator said the current authority, the Coast Protection Board, was virtually a "toothless tiger" with only advisory functions.

"Labor has had years of neglect for our beaches and the Liberals are dithering."

The body will be made up of experts including a marine geologist, a marine surveyor and a computer modeller to look at sand erosion.

South Australia heads to the polls on March 17.

Australian Associated Press