Scott Morrison has announced a cut in the planned backpacker tax from 32.5% to 19%, to be funded by an increased charge on all passengers leaving Australia.

The move has won plaudits from the National Farmers’ Federation but has angered Tourism & Transport Forum Australia, which has complained about the “blatant cash grab” of increasing the departure charge.

On Tuesday the treasurer announced that from 1 January the backpacker tax would be 19% of the first $37,000 that backpackers earn, confirming reports in Guardian Australia last week of a compromise to cut the tax.

The government will also try to attract backpackers by cutting the visa application charge by $50 to $390, increasing the age that backpackers can come to Australia to 35 and letting them work for the same employer for 12 months provided they change location after six months.

Morrison promised cutting the tax rate and visa fee would be revenue-neutral by raising $365m over four years through two other measures. The government will increase the passenger movement charge by $5 to $60, and will take 95% of foreign workers’ superannuation when they leave Australia.

Morrison said the purpose of the superannuation system was “to fund the retirement of Australians”, not foreign workers.

He said the changes were designed to encourage backpackers to come to Australia as they were an “important source of labour for the agricultural sector”. The new tax rate of 19% was “commensurate” with regimes in Canada, the UK and New Zealand, he said.

Morrison said the proposed changes had passed the cabinet and the government’s backbench committee, one member of which said they were as happy as “pigs in mud” with the policy.

Asked whether it would keep the Liberal National MP George Christensen – who threatened to quit the party over the policy – “in the tent”, the treasurer said Christensen was “always in the tent”.

The backpacker tax, which was due to take effect from 1 July but was delayed during the election campaign, was a surprise inclusion in the 2015 budget estimated to raise $540m.

The new 19% tax from the first dollar earned replaces a system that allows backpackers to access the $18,200 tax-free threshold and pay 19% for income above the tax-free threshold up to $37,000.

The National Farmers’ Federation chief executive, Tony Mahar, said it was important that parliament “recognise that this is really important for the growth sector that is agriculture” and pass the changes.

“We need to get the message out there [that the rate will be 19%],” Mahar told ABC24. “We need workers to know that Australia is open for business,”

He said the extra $5 departure charge was a “small increase … to allow us the agricultural and farming industry to have certainty for backpackers”.

The Tourism & Transport Forum chief executive, Margy Osmond, said she was “very disappointed” the government had pushed ahead with the backpacker tax, but lowering the rate to 19% was “a lot better”.

“Industry has been completely blindsided by this decision to increase the [departure charge] by $5 … at no point was it flagged in any discussions in which we took part,” she said.

“It is a bitter disappointment that we’ve been slapped with this tax hike on every traveller – Australian or international visitor – heading overseas.”

Labor’s agriculture spokesman, Joel Fitzgibbon, had previously suggested the opposition would support backpacker tax legislation if the Coalition revised the policy and found a more acceptable compromise. But at a press conference on Tuesday Bill Shorten said the opposition would not commit to a package that had just been announced.

Shorten said the backpacker tax was “poor policy, poorly executed” and the opposition would be “mugs to sign up to something this government says at first blush”.

In a separate press conference on Tuesday the deputy prime minister, Barnaby Joyce, said the government had now fixed its policy and he was sure the changes would “fly through the Nationals party room”.

In response to claims of a collapse in backpacker numbers owing to the tax, Joyce said they now had “exactly the same conditions” and taxes as last year because the government had delayed the tax increase to 1 January.

He said Labor had “banked the backpacker tax” yet had “never provided a solution” to the problem of the tax deterring backpackers, as it complained.