Prime Minister Scott Morrison will on Sunday announce a three-month extension to the popular program, which was scheduled to end on March 31.

Industry groups had been pressuring the government to continue the scheme beyond this month, with the Australian Chamber of Commerce and Industry saying the support had been vital in reversing a long-term decline in apprenticeship numbers.

Figures published on Friday showed there were more than 352,000 people in training as of last September - up 33 per cent from 12 months earlier.

The funding, to be included in Tuesday's budget, will form part of Mr Morrison's pitch during the upcoming federal election campaign, where the Coalition is desperate to shore up support among small business owners and tradespeople.

Under the extended scheme, employers who take on an apprentice or trainee before June 30 will be able to have their wages subsidised by 50 per cent for the first year - up to a maximum of $28,000.

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The wage subsidy will be reduced to 10 per cent in the second year, and 5 per cent in the third year.

The pandemic support scheme has already helped more than 73,000 businesses bring on an apprentice or trainee, with the government hopeful the extra funding will get an extra 35,000 people into a job.

Mr Morrison said investment in trades training helped shore up the skills pipeline, put people in work and provided businesses with the confidence to keep hiring.

"These programs deliver certainty for business so they can go and hire another apprentice chef, another apprentice hairdresser, another apprentice plumber. It is about getting Australians skilled and into jobs right now," Mr Morrison said.

Employment Minister Stuart Robert said Australia could not afford to lose the momentum it had gained in skills training, as he attacked Labor for a lack of policies in the area.