Shire of Northam President Steven Pollard said the extra 19 people were being housed in a disabled accommodation section of the centre.
‘The numbers at the centre tend to fluctuate,’ Mr Pollard said.
The Northam detention centre, which opened in June last year, is not alone.
Many other Australian detention centres are full as they struggle to cope with the flood of asylum seekers over the past year.
Department of Immigration and Citizenship statistics reveal there were 4783 people held in immigration detention facilities and alternative places of detention at January 31 of this year.
The numbers have grown steadily since then.
From January to April, 75 asylum seeker boats carrying 5031 passengers entered Australian waters.
Many asylum seekers are not held in full detention.
More than 2800 are in community detention and 10,000 are living in the community on bridging visas.
Local residents believe asylum seekers are staying in temporary accommodation in the Shire of Kalamunda.
A spokeswoman for the Department of Immigration and Citizenship Minister confirmed the Government had been using short-term transitional accommodation for bridging visa holders coming out of detention.
They could include caravan parks, motels and hotels.
The spokeswoman declined to comment on whether asylum seekers were being housed in the Shire of Kalamunda.
According to the Department of Immigration and Citizenships’ fact sheet on asylum seekers, people on bridging visas are able to choose where they live and receive a different level of support to people living in community detention.
The Government grants bridging visas to asylum seekers so they can live in the community while their visa application is being processed.