Immigration New Zealand will be getting $34 million more in operating funding to employ an additional 29 staff to increase screening of people entering New Zealand.
The Budget also provides $6.2m of new operating funding, plus $7.7m of new capital to support new refugee arrivals.
Immigration Minister Iain Lees-Galloway said the "significant investment" in immigration services was aimed at combating exploitation of migrants and improve visa processing.
"Eliminating the exploitation of migrants is one of this Government's top priorities. Our investment announced today will contribute to the early identification of people at risk of exploitation," Lees-Galloway said.
"An increase of $34 million of operating funding over the next four years will enable Immigration New Zealand to employ an additional 29 staff to increase screening and assessment of air passengers and help identify exploitation risks early," he said.
"Exploitation takes many forms, including outright slavery, undermining an individual's personal freedom, underpayment of wages, and failing to meet guaranteed minimum entitlements. These practices undermine human rights and the vast majority of businesses that do the right thing."
The Budget 2018 provides $20.9m in operating funding in 2017/18, $98.9m in operating funding over the following four years, and $12.5m in capital funding as INZ transitions to a new visa operating model.
INZ is changing to a new operating model through the Visa Services 2020 transformation programme beginning in 2019/20.
The Immigration Advisers Authority will be getting $5.6m to target unlawful immigration advisers.
"The changes respond to pressures on our border operations and increases in the number of visa applications as a result of significant growth in international visitor numbers in recent years," Lees-Galloway said.
The increased funding will be partially recovered from immigration fees ($113m over four years) and the Immigration Levy ($44.7m over four years).
Money will also be put towards improving the Mangere Refugee Resettlement Centre and additional resources for asylum and protection claims, and housing support for quota refugees.
Budget 2018 provides $6.2m of new operating funding over the next four years, plus $7.7m of new capital.
This is to build and operate two new accommodation blocks at the centre.
New operating funding of $3.8m over the next four years, plus $335,000 in 2017/18, has been allocated for the Refugee and Protection Unit.
"This will ensure that asylum and protection claims can be processed more quickly. It will also provide greater resources to assist refugees to find affordable housing, which has been increasingly challenging," Lees-Galloway said.
Massey University immigration expert Professor Paul Spoonley said the Minister had clearly signalled "the desire to manage those who might be exploiting migrants".
"The Budget delivers on both visa processing and what happens in the New Zealand labour market, but I expected something about international students and targeting low level qualifications and providers, and regionalising immigration" Spoonley said.
Spoonley said the Budget missed out on giving incentives to divert immigrants away from Auckland.
Simon Moore, director of New Zealand Association of Migration and Investment said he was sceptical that the 29 extra staff would be able to identify exploiters at the border.
"My experience would suggest that a lot of the exploitation is in the form of employers who are mostly New Zealand citizens and or residents," Moore said.
"Extra funding for INZ is always a good thing if it's channelled into the right areas and the technology side of INZ is certainly moving forward at pace and will be relied upon more as offshore branches close. It will require ongoing investment to keep up with the pace of change.
Moore said the extra funding of the IAA has also got to be channelled into the right area.
"One of the main concerns is the provision of immigration advice offshore by unlicensed persons, particularly in the student industry," he added.