A bad day for Australian workers got worse as Boeing announced up to 300 jobs would go from its Port Melbourne site.

More jobs are leaving Australia with 830 positions cut in just one day by three big employers.

Only hours after BP and Philip Morris announced 530 job cuts between them, Boeing on Wednesday evening said up to 300 jobs would go from its Port Melbourne site.

The aerospace giant said the jobs, mainly of contractors, would go by the end of 2014.

Philip Morris will also close its Moorabbin-based cigarette factory in Melbourne by the end of the year at the cost of 180 jobs.

BP’s Bulwer Island plant in Brisbane will shrink from 380 staff to just 25 by mid-2015, while another 300 contractors could be affected.

Boeing said it would work to minimise job losses by not filling open positions and natural attrition.

“In line with a long established financial forecast, we will be releasing up to 300 people, primarily fixed-term contractors, by the end of the year,” Boeing said in a statement issued on Wednesday night.

“Reducing employment on these programs is a natural part of the manufacturing cycle.

According to its website, Boeing Aerostructures Australia employs 1300 people at its Melbourne site, in design, test, certification and manufacture of advanced structures for commercial airplanes.

BP said the emergence of large low-cost oil refineries in Asia was the reason for its decision to close its Brisbane operations.

“While this decision will significantly improve our competitive position, it will result in job losses and I would like to acknowledge the enormous commitment and contribution made over many years by our staff at Bulwer Island,” BP Australasia president Andy Holmes said.

Tim Wall, the managing director of the Bulwer Island refinery, said it was a sad day for all of the plant’s staff.

“We will be putting measures in place to assist our affected employees, including transitional support and job placement assistance,” he said.

Philip Morris is sending its cigarette production to Korea, partly blaming over-regulation in Australia for the move.

John Gledhill, PMI managing director for Australia, New Zealand and the Pacific Islands, said the introduction in 2010 of reduced-fire risk requirements for Australian-made cigarettes had resulted in products that did not match consumers’ preferences in other markets in the region.

“Despite the introduction of plain packaging and the continued growth in illicit trade, PML’s volumes were stable in 2013,” Mr Gledhill said in a statement on Wednesday.

“However, with any significant export opportunity restricted by Australian government regulations, our Moorabbin factory is significantly under-utilised, operating at less than half of its currently installed capacity.”

The Australian Workers Union said it was in negotiations with the company over the shutdown.

“These are people who have done an honest job, been loyal to their employer and contributed to the life of this state. They need jobs,” AWU Victorian secretary Ben Davis said.