PERTH - Hundreds of iron-ore miner BHP's electrical workers at Port Hedland in Western Australia will vote on potential strike action, a union said on Friday, raising the risk of disruptions to iron-ore shipments from one of the world's biggest export hubs.

The Electrical Trades Union (ETU) said it had begun the process for its members to authorise a strike, which could "very likely" take place by the end of June if a pay deal was not reached.

The prospect of a strike comes after six months of stalled talks with BHP, the world's biggest listed miner, to agree on a labour agreement, with workers seeking improved pay and conditions.

"Our members haven't taken this lightly," Adam Woodage, the union's State secretary, said at a press conference in Perth.

"BHP have stalled negotiations for up to six months. There's been little movement from the company, and what movement has come has been an insult to our members."

A strike would have a "significant impact on operations" and could bring the export hub to a halt, Woodage added.

A BHP spokesperson said the miner was negotiating a new agreement with its port operations teams.

"In the event of union disruptions at our sites, we have strong contingency plans in place to protect our people and ensure safe, reliable operations can continue," the spokesperson added.

Port Hedland is one of the largest iron-ore loading ports in the world and the largest in Australia. It is linked to a number of BHP's mines in the Pilbara region and is used for all of its iron-ore exports in Western Australia.

BHP's labour agreement covers around 450 port workers, of whom about 200 are ETU members.

Unionised workers will vote in the next two weeks to endorse work stoppages ranging from 15 minutes to 24 hours, the ETU said.

"We anticipate they'll endorse taking that action," Woodage said.

"BHP had a A$15-billion ($10.73-billion) profit (last year) ... so there's plenty of money in the bank for BHP to share with their workers, and our members are seeking a slice of that money."

BHP's shares were up 1.4% at A$61.45 in afternoon trade, in line with the broader benchmark S&P/ASX 200 index, which was up 1.2%.

Separately, the ETU is engaged in labour bargaining talks with Japan's Inpex alongside the Offshore Alliance union for workers at the Ichthys gas plant in Darwin.

Offshore Alliance, made up of the Australian Workers' Union and the Maritime Union of Australia, said on Friday that planned strike action had been delayed until June 2 as talks progressed.