LOS ANGELES, United States (AFP) — California is set to become the first US state to offer healthcare to some adults living in the country illegally, after lawmakers on Sunday approved the measure expected to cost almost US$100 million.

Under the plan supported by Democrats in the state legislature, adults between the ages of 19 and 25 can qualify for healthcare through Medi-Cal, the state’s health insurance program for low income residents that was expanded under President Barack Obama.

The agreement, which came after months of negotiations, is part of the 2019-2020 state budget of US$213 billion that is set to be approved this week and which will come into effect in July.

The expanded health coverage, which will cover an additional 90,000 people, will take effect in January of next year.

Lawmakers were able to approve the measure thanks in part to California, which has the fifth largest economy in the world, having the biggest budget surplus in history — over US$20 billion.

Democratic lawmakers who hold the majority in the state legislature had initially proposed that all low-income adults, regardless of immigration status, should be offered Medi-Cal coverage.

That state’s governor, Gavin Newsom, however balked at the proposal given the steep price estimated at US$3.4 billion.

Republicans have also criticised the proposal to provide Medi-Cal coverage for immigrants saying it would amount to an unfair tax burden on Americans.